AlanF

JW Insider
Nope. it works therefore it is that strong cable as it led to the ending of the Gentile Times in 1914 CE a reality proved by the outbreak of the Great War with the birth of God's Heavenly Kingdom . You need not only to properly understand History and Chronology but Biblical Theology namely Salvation History.
scholar JW

CC let them stew in their own " self-importance" and self-deceit....... and go and mislead others.   They will not mislead us.  I have looked at this again and again and found their nit-picking to be without substance.  I have actually lost some  respect for them, that which I had when I started on this forum.
The reason, they only debate, but do not fully understand the main theme of the bible and the importance if the chronology time line as the JWs understand it (with the help of Jehovah) right now.  They give credence to secular scholars but reject the bible's own chronology. This is why they come up with ideas which say that 1914 is bogus, the interpretation of nebuchadrezzar dream is bogus, the signs of 'perousia' are bogus etc. Etc. ...... and some dare to think of themselves as "enlightened" or scholarly witnesses.
JW teachings are crucial to understand the thinking of jehovah and how jehovah cares about us. He wants us to understand where we are in the stream of time to keep active and our hope secure.
Our timeline  fits in with the time-line of the 7 heads of the beast - something which they have not looked at or consider important because they do not accept WW1 and league of nations as a "sign"  they do not accept WW2 and creation of UN as part of the "sign"....  .during perousia..
We are already living under the "image if the beast" ...... which soon will receive more power (like an 8th king) and they do not even consider how this fits into what ithey are debating. They are focussing on only one room of an entire ocean liner (Titanic) while the entire boat is sinking. They are so busy debating about one room that they do not notice the final signs, which is part of this time-line of succession of the "beasts" and image of the beast which takes place during the "perousia".  
Then you have " self-heroes like alanf" with his scoffing and name-calling ( like an off-key chorus in the background.)..... quite a crazy way to dominate a conversation...... lol. 
Does this bring them in line for life under Jehovah's government?  Definitely not.  This is a futile exercise ........ being an expert in one part of the boat and not taking note of the ENTIRE boat. 

This moron is not only irredeemably lazy, but stupid enough to think that he can lay a trap for JW critics by proposing a silly task that, as you and I have pointed out, can easily be accomplished via Google. I even pointed him to a website that does Julian to Gregorian conversion, etc., as well as to definitive Watchtower statements about the 539 date. I don't know what this charlatan's game is here, but I ain't playing along anymore.

This moron is not only irredeemably lazy, but stupid enough to think that he can lay a trap for JW critics by proposing a silly task that, as you and I have pointed out, can easily be accomplished via Google. I even pointed him to a website that does Julian to Gregorian conversion, etc., as well as to definitive Watchtower statements about the 539 date. I don't know what this charlatan's game is here, but I ain't playing along anymore.

I know you don't actually expect this ignorant, arrogant moron to understand any of that.

Again demonstrating Dunning-Kruger to perfection. You wouldn't recognize real scholarship if it bit you on your African ass.

Nope. I apply the term to those who demonstrate that they're too stupid to realize how stupid they are.

You've already proved it. Look in the mirror.
Bullshit. Give some examples. If you dare.
Which you are obviously too stupid to understand. You are apparently going on obsolete Watchtower writings from more than 50 years ago.
You're not describing "bible chronology" but Watchtower chronology. And it was thoroughly debunked decades ago.
Tell that to the writers of the Insight book.
Bullshit. 
The dating was used to make the predictions, you moron!
So?
LOL! Such abysmal ignorance.

Wrong. Only parts of the place were buried. Excavations were done on the buried parts. Yet again you demonstrate atrocious reading comprehension. https://en.wikipedia.org/wiki/Pasargadae
Wrong again. Most of Troy was never buried. It was so badly ruined that no explorers recognized it.
So? There are only dry riverbeds in Sinai. Apples and oranges.
So you actually think that ALL TRACES of 3 million people wandering in a desert wilderness for 40 years could magically disappear. That is called rationalization -- rationalization on a massive scale.
Keep in mind that explorers have searched for evidence of the Exodus in Sinai for well over 200 years. Archaeologists who were extremely eager to find something. Even today, with satellite imaging, eager Israeli and Bible-believing Christians can find nothing. Not even though satellite imaging has revealed all manner of buried structures in Egypt proper.
Desperation to believe in myths is a great motivator for creative rationalization.

CC is too stupid to be confused.

CC is too stupid to be confused.

That reminds me . . . a few posts back, AlanF mentioned an article on JSTOR that was behind a paywall, and a lot of JSTOR documents are very expensive. I have full access to JSTOR as a college alumni, but I am required to follow the university's instructions about "fair use" doctrines, or I could lose the privilege, and the same university allows access to a lot of other databases.
But the point is that everyone should know that (since nearly the beginning of Covid-19) JSTOR has been offering everyone, student or individual researcher, free access to up to 100 articles a month, and a few downloads too. They have extended this offer into next year, which was originally going to stop this year.
Also, there are a lot of articles, books and journals referenced on Academia.edu that are free, but there are a lot that are referenced but haven't been uploaded due to copyright issues. In fact, when I noticed that John Steele's article in "Keeping Watch in Babylon" was not available, I made a request through Academia.edu and it wasn't John Steele that answered but Kathryn Stevens.
At any rate, Kathryn Stevens wrote back within an hour saying:
Kathryn Stevens    University of Oxford       Faculty Member, Faculty of Classics, Ancient History     4 days Kathryn Stevens Dear xxxxx xxxxxxxxx,
I saw you requested an upload of my book with John Steele and Johannes Haubold on the Astronomical Diaries – for copyright reasons I can't upload it to academia.edu but would be very happy to share a pdf via email/WeTransfer if you would like one! My email address is xxxxxxxxxxxxxxx@ccc.ox.ac.uk if you want to contact me that way.
Best wishes,
Kathryn Sometimes it's easier to get material for discussion than people might think. Scholars are often happy to have their work discussed online. (It's also available illegally, I think, on dokument.pub or some such site.)

CC, I know you weren't asking me, but I appreciated that this section showed the value of VAT 4956 as a true astronomical diary, much closer in format to the style and content of later diaries, so that it would not be classed with what John Steele would call the proto-diaries from the previous centuries when the format of these diaries was not so well established. For context I am providing the final two paragraphs of his summary. I highlighted the area I assume you were asking about. (BTW, I thought this whole article was excellent, but not until reading it in its entirety.)

And the chart on page 45:

 

You're welcome.
Now that this material has been posted -- and it contains everything relevant from the 2016 Watchtower CD Library -- those posters too lazy or too stupid or too afraid to look for themselves have no excuse.

Several of our less enlightened posters have made claims that are quite ridiculous, and indicate a nearly complete lack of familiarity with what they're talking about. Arauna, for example, focuses on the vague notion -- which she never explains coherently -- that the Greek Olympiads are somehow a better source for dating the reign of Cyrus the Great than are astronomical tablets in conjunction with Persian contract tablets and other contemporary documents. But the Watchtower Society disagrees, as I will now show.
Watchtower publications contain several mentions of the Greek Olympiads, such as these:
Insight, Vol. 1, p. 447
<< The Greeks figured time by means of four-year periods called Olympiads, starting from the first Olympiad, calculated as beginning in 776 B.C.E. Additionally, they often identified specific years by referring to the term of office of some particular official. >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
Note that the Greek historian Diodorus Siculus is referenced as the source of the statements about the Olympiads.
A question that arises is, How reliable are the histories of Diodorus Siculus? Note what the Watchtower Society had to say about these:
The Watchtower, April 1, 1969, pp. 222-223
<< But what about the later historians of the Greeks and the Romans? Do they supply chronology that is sufficiently exact that it poses a serious challenge to the Bible’s record? Among them we may consider Diodorus Siculus (1st century B.C.E.). Of the original forty books of his history, only fifteen have come down to us. Five of these deal with the mythic history of Egypt, Assyria, Ethiopia and Greece, and the remainder chronicle the second Persian war and extend to the time of Alexander the Great’s successors. It is said of Diodorus that “he has been at little pains to sift his materials, and hence frequent repetitions and contradictions may be found in the body of the work. . . . In the chronology of the strictly historical period he is occasionally inaccurate.”—The Encyclopædia Britannica, 9th edition, Volume 7, page 245. >>
So the Society itself argues that Diodorus' histories must be taken with a good grain of salt.
Nevertheless, any ancient source like Diodorus can be quite accurate in its chronology. Diodorus, it turns out, is accurate for at least the period in question here, 539 BCE through about 485 BCE. Note what the Society said about how Diodorus' dating by Olympiads matches up with dating by various other ancient documents:
The Watchtower, May 15, 1971, p. 316
<< Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. >>
Next note what the Insight book had to say about this:
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Pretty much the same as the above 1971 Watchtower said.
However, this description of the evidence for 539 BCE was incomplete (more complete information was given on page 453). Another Watchtower publication also gave more complete information:
The Watchtower, October 1, 2011, p. 28
<< A PIVOTAL DATE IN HISTORY
The date 539 B.C.E. when Cyrus II conquered Babylon is calculated using the testimony of:
Ancient historical sources and cuneiform tablets: Diodorus of Sicily (c. 80-20 B.C.E.) wrote that Cyrus became king of Persia in “the opening year of the Fifty-fifth Olympiad.” (Historical Library, Book IX, 21) That year was 560 B.C.E. The Greek historian Herodotus (c. 485-425 B.C.E.) stated that Cyrus was killed “after he had reigned twenty-nine years,” which would put his death during his 30th year, in 530 B.C.E. (Histories, Book I, Clio, 214) Cuneiform tablets show that Cyrus ruled Babylon for nine years before his death. Thus, nine years prior to his death in 530 B.C.E. takes us back to 539 B.C.E. as the year Cyrus conquered Babylon.
Confirmation by a cuneiform tablet: A Babylonian astronomical clay tablet (BM 33066) confirms the date of Cyrus’ death in 530 B.C.E. Though this tablet contains some errors regarding the astronomical positions, it contains the descriptions of two lunar eclipses that the tablet says occurred in the seventh year of Cambyses II, the son and successor of Cyrus. These are identified with lunar eclipses visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E., thus pointing to the spring of 523 B.C.E. as the beginning of Cambyses’ seventh year. That would make his first regnal year 529 B.C.E. So Cyrus’ last year would have been 530 B.C.E., making 539 B.C.E. his first year of ruling Babylon. >>
Note clearly that the second point uses astronomical dating to arrive at 539 BCE for the first year of Cyrus' ruling Babylon: Two eclipses, 523 and 522 BCE, point to the 7th year of Cambyses, so his 1st year was 529, and the 9th year of his predecessor Cyrus was 530 BCE, thus arriving at 538 BCE as Cyrus' 1st year, and 539 as his accession year (counted as year zero in the Babylonian dating system).
Thus, this 2011 Watchtower article was forced to admit that a contemporary Persian astronomical tablet, along with cuneiform documents and contract tablets that establish that Cambyses reigned for seven years and Cyrus reigned for nine years, solidly point to the date that the Watchtower Society uses as "a pivotal date in history".
Also note that the above Watchtower material admits that the Royal Canon of Ptolemy accurately shows the fall of Babylon in 539 BCE.
That these sources all converge on 539 BCE as the date of Babylon's overthrow is agreed to in the following Watchtower material:
All Scripture Is Inspired, pp. 282-283
<< 28 Pivotal Date for the Hebrew Scriptures. A prominent event recorded both in the Bible and in secular history is the overthrow of the city of Babylon by the Medes and Persians under Cyrus. The Bible records this event at Daniel 5:30. Various historical sources (including Diodorus, Africanus, Eusebius, Ptolemy, and the Babylonian tablets) support 539 B.C.E. as the year for the overthrow of Babylon by Cyrus. The Nabonidus Chronicle gives the month and day of the city’s fall (the year is missing). Secular chronologers have thus set the date for the fall of Babylon as October 11, 539 B.C.E., according to the Julian calendar, or October 5 by the Gregorian calendar.
29 Following the overthrow of Babylon, and during his first year as ruler of conquered Babylon, Cyrus issued his famous decree permitting the Jews to return to Jerusalem. In view of the Bible record, the decree was likely made late in 538 B.C.E. or toward the spring of 537 B.C.E. This would give ample opportunity for the Jews to resettle in their homeland and to come up to Jerusalem to restore the worship of Jehovah in “the seventh month,” Tishri, or about October 1, 537 B.C.E.—Ezra 1:1-4; 3:1-6. >>
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Insight, Vol. 1, p. 458
<< Another date that can be used as a pivotal point is the year 539 B.C.E., supported by various historical sources as the year for the overthrow of Babylon by Cyrus the Persian. (Secular sources for Cyrus’ reign include Diodorus, Africanus, Eusebius, and Ptolemy, as well as the Babylonian tablets.) >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
The Watchtower, May 15, 2003, p. 4
<< One pivotal date is 539 B.C.E., the year when Persian King Cyrus overthrew Babylon. Secular sources for the time of his reign include Babylonian tablets and documents of Diodorus, Africanus, Eusebius, and Ptolemy. >>
Quoted above, but here it is again:
The Watchtower, May 15, 1971, p. 316
Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. 
And finally we have the Society's authoritative and more detailed statement summarizing the above information:
Insight, Vol. 1, pp. 452-453
<< Babylonian Chronology. Babylon enters the Biblical picture principally from the time of Nebuchadnezzar II onward. The reign of Nebuchadnezzar’s father Nabopolassar marked the start of what is called the Neo-Babylonian Empire; it ended with the reigns of Nabonidus and his son Belshazzar and the overthrow of Babylon by Cyrus the Persian. This period is of great interest to Bible scholars since it embraces the time of the Babylonian destruction of Jerusalem and the greater part of the 70-year period of Jewish exile.
Jeremiah 52:28 says that in the seventh year of Nebuchadnezzar (or Nebuchadrezzar) the first group of Jewish exiles was taken to Babylon. In harmony with this, a cuneiform inscription of the Babylonian Chronicle (British Museum 21946) states: “The seventh year: In the month Kislev the king of Akkad mustered his army and marched to Hattu. He encamped against the city of Judah and on the second day of the month Adar he captured the city (and) seized (its) king [Jehoiachin]. A king of his own choice [Zedekiah] he appointed in the city (and) taking the vast tribute he brought it into Babylon.” (Assyrian and Babylonian Chronicles, by A. K. Grayson, 1975, p. 102; compare 2Ki 24:1-17; 2Ch 36:5-10.) (PICTURE, Vol. 2, p. 326) For the final 32 years of Nebuchadnezzar’s reign, there are no historical records of the chronicle type except a fragmentary inscription of a campaign against Egypt in Nebuchadnezzar’s 37th year.
For Awil-Marduk (Evil-merodach, 2Ki 25:27, 28), tablets dated up to his second year of rule have been found. For Neriglissar, considered to be the successor of Awil-Marduk, contract tablets are known dated to his fourth year.
A Babylonian clay tablet is helpful for connecting Babylonian chronology with Biblical chronology. This tablet contains the following astronomical information for the seventh year of Cambyses II son of Cyrus II: “Year 7, Tammuz, night of the 14th, 1 2⁄3 double hours [three hours and twenty minutes] after night came, a lunar eclipse; visible in its full course; it reached over the northern half disc [of the moon]. Tebet, night of the 14th, two and a half double hours [five hours] at night before morning [in the latter part of the night], the disc of the moon was eclipsed; the whole course visible; over the southern and northern part the eclipse reached.” (Inschriften von Cambyses, König von Babylon, by J. N. Strassmaier, Leipzig, 1890, No. 400, lines 45-48; Sternkunde und Sterndienst in Babel, by F. X. Kugler, Münster, 1907, Vol. I, pp. 70, 71) These two lunar eclipses can evidently be identified with the lunar eclipses that were visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E. (Oppolzer’s Canon of Eclipses, translated by O. Gingerich, 1962, p. 335) Thus, this tablet points to the spring of 523 B.C.E. as the beginning of the seventh year of Cambyses II.
Since the seventh year of Cambyses II began in spring of 523 B.C.E., his first year of rule was 529 B.C.E. and his accession year, and the last year of Cyrus II as king of Babylon, was 530 B.C.E. The latest tablet dated in the reign of Cyrus II is from the 5th month, 23rd day of his 9th year. (Babylonian Chronology, 626 B.C.–A.D. 75, by R. Parker and W. Dubberstein, 1971, p. 14) As the ninth year of Cyrus II as king of Babylon was 530 B.C.E., his first year according to that reckoning was 538 B.C.E. and his accession year was 539 B.C.E. >>
Note that all of the above material proves that the Watchtower Society agrees that Cyrus' accession year began about October 539 BCE, and his 1st regnal year began Nisan 1, 538 BCE.
The poster "ScholarJW" has vaguely implied that in some unspecified way the rule of Darius the Mede must be fit in with that of Cyrus. Obviously, the Society disagrees, since it says nothing about Darius the Mede in any of the above material. In some older Watchtower publications the identity of Darius the Mede is discussed, but in no case does that change the dates for Cyrus' reign.
I hope this material provides some useful source material for our astute posters.

Several of our less enlightened posters have made claims that are quite ridiculous, and indicate a nearly complete lack of familiarity with what they're talking about. Arauna, for example, focuses on the vague notion -- which she never explains coherently -- that the Greek Olympiads are somehow a better source for dating the reign of Cyrus the Great than are astronomical tablets in conjunction with Persian contract tablets and other contemporary documents. But the Watchtower Society disagrees, as I will now show.
Watchtower publications contain several mentions of the Greek Olympiads, such as these:
Insight, Vol. 1, p. 447
<< The Greeks figured time by means of four-year periods called Olympiads, starting from the first Olympiad, calculated as beginning in 776 B.C.E. Additionally, they often identified specific years by referring to the term of office of some particular official. >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
Note that the Greek historian Diodorus Siculus is referenced as the source of the statements about the Olympiads.
A question that arises is, How reliable are the histories of Diodorus Siculus? Note what the Watchtower Society had to say about these:
The Watchtower, April 1, 1969, pp. 222-223
<< But what about the later historians of the Greeks and the Romans? Do they supply chronology that is sufficiently exact that it poses a serious challenge to the Bible’s record? Among them we may consider Diodorus Siculus (1st century B.C.E.). Of the original forty books of his history, only fifteen have come down to us. Five of these deal with the mythic history of Egypt, Assyria, Ethiopia and Greece, and the remainder chronicle the second Persian war and extend to the time of Alexander the Great’s successors. It is said of Diodorus that “he has been at little pains to sift his materials, and hence frequent repetitions and contradictions may be found in the body of the work. . . . In the chronology of the strictly historical period he is occasionally inaccurate.”—The Encyclopædia Britannica, 9th edition, Volume 7, page 245. >>
So the Society itself argues that Diodorus' histories must be taken with a good grain of salt.
Nevertheless, any ancient source like Diodorus can be quite accurate in its chronology. Diodorus, it turns out, is accurate for at least the period in question here, 539 BCE through about 485 BCE. Note what the Society said about how Diodorus' dating by Olympiads matches up with dating by various other ancient documents:
The Watchtower, May 15, 1971, p. 316
<< Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. >>
Next note what the Insight book had to say about this:
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Pretty much the same as the above 1971 Watchtower said.
However, this description of the evidence for 539 BCE was incomplete (more complete information was given on page 453). Another Watchtower publication also gave more complete information:
The Watchtower, October 1, 2011, p. 28
<< A PIVOTAL DATE IN HISTORY
The date 539 B.C.E. when Cyrus II conquered Babylon is calculated using the testimony of:
Ancient historical sources and cuneiform tablets: Diodorus of Sicily (c. 80-20 B.C.E.) wrote that Cyrus became king of Persia in “the opening year of the Fifty-fifth Olympiad.” (Historical Library, Book IX, 21) That year was 560 B.C.E. The Greek historian Herodotus (c. 485-425 B.C.E.) stated that Cyrus was killed “after he had reigned twenty-nine years,” which would put his death during his 30th year, in 530 B.C.E. (Histories, Book I, Clio, 214) Cuneiform tablets show that Cyrus ruled Babylon for nine years before his death. Thus, nine years prior to his death in 530 B.C.E. takes us back to 539 B.C.E. as the year Cyrus conquered Babylon.
Confirmation by a cuneiform tablet: A Babylonian astronomical clay tablet (BM 33066) confirms the date of Cyrus’ death in 530 B.C.E. Though this tablet contains some errors regarding the astronomical positions, it contains the descriptions of two lunar eclipses that the tablet says occurred in the seventh year of Cambyses II, the son and successor of Cyrus. These are identified with lunar eclipses visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E., thus pointing to the spring of 523 B.C.E. as the beginning of Cambyses’ seventh year. That would make his first regnal year 529 B.C.E. So Cyrus’ last year would have been 530 B.C.E., making 539 B.C.E. his first year of ruling Babylon. >>
Note clearly that the second point uses astronomical dating to arrive at 539 BCE for the first year of Cyrus' ruling Babylon: Two eclipses, 523 and 522 BCE, point to the 7th year of Cambyses, so his 1st year was 529, and the 9th year of his predecessor Cyrus was 530 BCE, thus arriving at 538 BCE as Cyrus' 1st year, and 539 as his accession year (counted as year zero in the Babylonian dating system).
Thus, this 2011 Watchtower article was forced to admit that a contemporary Persian astronomical tablet, along with cuneiform documents and contract tablets that establish that Cambyses reigned for seven years and Cyrus reigned for nine years, solidly point to the date that the Watchtower Society uses as "a pivotal date in history".
Also note that the above Watchtower material admits that the Royal Canon of Ptolemy accurately shows the fall of Babylon in 539 BCE.
That these sources all converge on 539 BCE as the date of Babylon's overthrow is agreed to in the following Watchtower material:
All Scripture Is Inspired, pp. 282-283
<< 28 Pivotal Date for the Hebrew Scriptures. A prominent event recorded both in the Bible and in secular history is the overthrow of the city of Babylon by the Medes and Persians under Cyrus. The Bible records this event at Daniel 5:30. Various historical sources (including Diodorus, Africanus, Eusebius, Ptolemy, and the Babylonian tablets) support 539 B.C.E. as the year for the overthrow of Babylon by Cyrus. The Nabonidus Chronicle gives the month and day of the city’s fall (the year is missing). Secular chronologers have thus set the date for the fall of Babylon as October 11, 539 B.C.E., according to the Julian calendar, or October 5 by the Gregorian calendar.
29 Following the overthrow of Babylon, and during his first year as ruler of conquered Babylon, Cyrus issued his famous decree permitting the Jews to return to Jerusalem. In view of the Bible record, the decree was likely made late in 538 B.C.E. or toward the spring of 537 B.C.E. This would give ample opportunity for the Jews to resettle in their homeland and to come up to Jerusalem to restore the worship of Jehovah in “the seventh month,” Tishri, or about October 1, 537 B.C.E.—Ezra 1:1-4; 3:1-6. >>
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Insight, Vol. 1, p. 458
<< Another date that can be used as a pivotal point is the year 539 B.C.E., supported by various historical sources as the year for the overthrow of Babylon by Cyrus the Persian. (Secular sources for Cyrus’ reign include Diodorus, Africanus, Eusebius, and Ptolemy, as well as the Babylonian tablets.) >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
The Watchtower, May 15, 2003, p. 4
<< One pivotal date is 539 B.C.E., the year when Persian King Cyrus overthrew Babylon. Secular sources for the time of his reign include Babylonian tablets and documents of Diodorus, Africanus, Eusebius, and Ptolemy. >>
Quoted above, but here it is again:
The Watchtower, May 15, 1971, p. 316
Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. 
And finally we have the Society's authoritative and more detailed statement summarizing the above information:
Insight, Vol. 1, pp. 452-453
<< Babylonian Chronology. Babylon enters the Biblical picture principally from the time of Nebuchadnezzar II onward. The reign of Nebuchadnezzar’s father Nabopolassar marked the start of what is called the Neo-Babylonian Empire; it ended with the reigns of Nabonidus and his son Belshazzar and the overthrow of Babylon by Cyrus the Persian. This period is of great interest to Bible scholars since it embraces the time of the Babylonian destruction of Jerusalem and the greater part of the 70-year period of Jewish exile.
Jeremiah 52:28 says that in the seventh year of Nebuchadnezzar (or Nebuchadrezzar) the first group of Jewish exiles was taken to Babylon. In harmony with this, a cuneiform inscription of the Babylonian Chronicle (British Museum 21946) states: “The seventh year: In the month Kislev the king of Akkad mustered his army and marched to Hattu. He encamped against the city of Judah and on the second day of the month Adar he captured the city (and) seized (its) king [Jehoiachin]. A king of his own choice [Zedekiah] he appointed in the city (and) taking the vast tribute he brought it into Babylon.” (Assyrian and Babylonian Chronicles, by A. K. Grayson, 1975, p. 102; compare 2Ki 24:1-17; 2Ch 36:5-10.) (PICTURE, Vol. 2, p. 326) For the final 32 years of Nebuchadnezzar’s reign, there are no historical records of the chronicle type except a fragmentary inscription of a campaign against Egypt in Nebuchadnezzar’s 37th year.
For Awil-Marduk (Evil-merodach, 2Ki 25:27, 28), tablets dated up to his second year of rule have been found. For Neriglissar, considered to be the successor of Awil-Marduk, contract tablets are known dated to his fourth year.
A Babylonian clay tablet is helpful for connecting Babylonian chronology with Biblical chronology. This tablet contains the following astronomical information for the seventh year of Cambyses II son of Cyrus II: “Year 7, Tammuz, night of the 14th, 1 2⁄3 double hours [three hours and twenty minutes] after night came, a lunar eclipse; visible in its full course; it reached over the northern half disc [of the moon]. Tebet, night of the 14th, two and a half double hours [five hours] at night before morning [in the latter part of the night], the disc of the moon was eclipsed; the whole course visible; over the southern and northern part the eclipse reached.” (Inschriften von Cambyses, König von Babylon, by J. N. Strassmaier, Leipzig, 1890, No. 400, lines 45-48; Sternkunde und Sterndienst in Babel, by F. X. Kugler, Münster, 1907, Vol. I, pp. 70, 71) These two lunar eclipses can evidently be identified with the lunar eclipses that were visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E. (Oppolzer’s Canon of Eclipses, translated by O. Gingerich, 1962, p. 335) Thus, this tablet points to the spring of 523 B.C.E. as the beginning of the seventh year of Cambyses II.
Since the seventh year of Cambyses II began in spring of 523 B.C.E., his first year of rule was 529 B.C.E. and his accession year, and the last year of Cyrus II as king of Babylon, was 530 B.C.E. The latest tablet dated in the reign of Cyrus II is from the 5th month, 23rd day of his 9th year. (Babylonian Chronology, 626 B.C.–A.D. 75, by R. Parker and W. Dubberstein, 1971, p. 14) As the ninth year of Cyrus II as king of Babylon was 530 B.C.E., his first year according to that reckoning was 538 B.C.E. and his accession year was 539 B.C.E. >>
Note that all of the above material proves that the Watchtower Society agrees that Cyrus' accession year began about October 539 BCE, and his 1st regnal year began Nisan 1, 538 BCE.
The poster "ScholarJW" has vaguely implied that in some unspecified way the rule of Darius the Mede must be fit in with that of Cyrus. Obviously, the Society disagrees, since it says nothing about Darius the Mede in any of the above material. In some older Watchtower publications the identity of Darius the Mede is discussed, but in no case does that change the dates for Cyrus' reign.
I hope this material provides some useful source material for our astute posters.

Several of our less enlightened posters have made claims that are quite ridiculous, and indicate a nearly complete lack of familiarity with what they're talking about. Arauna, for example, focuses on the vague notion -- which she never explains coherently -- that the Greek Olympiads are somehow a better source for dating the reign of Cyrus the Great than are astronomical tablets in conjunction with Persian contract tablets and other contemporary documents. But the Watchtower Society disagrees, as I will now show.
Watchtower publications contain several mentions of the Greek Olympiads, such as these:
Insight, Vol. 1, p. 447
<< The Greeks figured time by means of four-year periods called Olympiads, starting from the first Olympiad, calculated as beginning in 776 B.C.E. Additionally, they often identified specific years by referring to the term of office of some particular official. >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
Note that the Greek historian Diodorus Siculus is referenced as the source of the statements about the Olympiads.
A question that arises is, How reliable are the histories of Diodorus Siculus? Note what the Watchtower Society had to say about these:
The Watchtower, April 1, 1969, pp. 222-223
<< But what about the later historians of the Greeks and the Romans? Do they supply chronology that is sufficiently exact that it poses a serious challenge to the Bible’s record? Among them we may consider Diodorus Siculus (1st century B.C.E.). Of the original forty books of his history, only fifteen have come down to us. Five of these deal with the mythic history of Egypt, Assyria, Ethiopia and Greece, and the remainder chronicle the second Persian war and extend to the time of Alexander the Great’s successors. It is said of Diodorus that “he has been at little pains to sift his materials, and hence frequent repetitions and contradictions may be found in the body of the work. . . . In the chronology of the strictly historical period he is occasionally inaccurate.”—The Encyclopædia Britannica, 9th edition, Volume 7, page 245. >>
So the Society itself argues that Diodorus' histories must be taken with a good grain of salt.
Nevertheless, any ancient source like Diodorus can be quite accurate in its chronology. Diodorus, it turns out, is accurate for at least the period in question here, 539 BCE through about 485 BCE. Note what the Society said about how Diodorus' dating by Olympiads matches up with dating by various other ancient documents:
The Watchtower, May 15, 1971, p. 316
<< Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. >>
Next note what the Insight book had to say about this:
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Pretty much the same as the above 1971 Watchtower said.
However, this description of the evidence for 539 BCE was incomplete (more complete information was given on page 453). Another Watchtower publication also gave more complete information:
The Watchtower, October 1, 2011, p. 28
<< A PIVOTAL DATE IN HISTORY
The date 539 B.C.E. when Cyrus II conquered Babylon is calculated using the testimony of:
Ancient historical sources and cuneiform tablets: Diodorus of Sicily (c. 80-20 B.C.E.) wrote that Cyrus became king of Persia in “the opening year of the Fifty-fifth Olympiad.” (Historical Library, Book IX, 21) That year was 560 B.C.E. The Greek historian Herodotus (c. 485-425 B.C.E.) stated that Cyrus was killed “after he had reigned twenty-nine years,” which would put his death during his 30th year, in 530 B.C.E. (Histories, Book I, Clio, 214) Cuneiform tablets show that Cyrus ruled Babylon for nine years before his death. Thus, nine years prior to his death in 530 B.C.E. takes us back to 539 B.C.E. as the year Cyrus conquered Babylon.
Confirmation by a cuneiform tablet: A Babylonian astronomical clay tablet (BM 33066) confirms the date of Cyrus’ death in 530 B.C.E. Though this tablet contains some errors regarding the astronomical positions, it contains the descriptions of two lunar eclipses that the tablet says occurred in the seventh year of Cambyses II, the son and successor of Cyrus. These are identified with lunar eclipses visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E., thus pointing to the spring of 523 B.C.E. as the beginning of Cambyses’ seventh year. That would make his first regnal year 529 B.C.E. So Cyrus’ last year would have been 530 B.C.E., making 539 B.C.E. his first year of ruling Babylon. >>
Note clearly that the second point uses astronomical dating to arrive at 539 BCE for the first year of Cyrus' ruling Babylon: Two eclipses, 523 and 522 BCE, point to the 7th year of Cambyses, so his 1st year was 529, and the 9th year of his predecessor Cyrus was 530 BCE, thus arriving at 538 BCE as Cyrus' 1st year, and 539 as his accession year (counted as year zero in the Babylonian dating system).
Thus, this 2011 Watchtower article was forced to admit that a contemporary Persian astronomical tablet, along with cuneiform documents and contract tablets that establish that Cambyses reigned for seven years and Cyrus reigned for nine years, solidly point to the date that the Watchtower Society uses as "a pivotal date in history".
Also note that the above Watchtower material admits that the Royal Canon of Ptolemy accurately shows the fall of Babylon in 539 BCE.
That these sources all converge on 539 BCE as the date of Babylon's overthrow is agreed to in the following Watchtower material:
All Scripture Is Inspired, pp. 282-283
<< 28 Pivotal Date for the Hebrew Scriptures. A prominent event recorded both in the Bible and in secular history is the overthrow of the city of Babylon by the Medes and Persians under Cyrus. The Bible records this event at Daniel 5:30. Various historical sources (including Diodorus, Africanus, Eusebius, Ptolemy, and the Babylonian tablets) support 539 B.C.E. as the year for the overthrow of Babylon by Cyrus. The Nabonidus Chronicle gives the month and day of the city’s fall (the year is missing). Secular chronologers have thus set the date for the fall of Babylon as October 11, 539 B.C.E., according to the Julian calendar, or October 5 by the Gregorian calendar.
29 Following the overthrow of Babylon, and during his first year as ruler of conquered Babylon, Cyrus issued his famous decree permitting the Jews to return to Jerusalem. In view of the Bible record, the decree was likely made late in 538 B.C.E. or toward the spring of 537 B.C.E. This would give ample opportunity for the Jews to resettle in their homeland and to come up to Jerusalem to restore the worship of Jehovah in “the seventh month,” Tishri, or about October 1, 537 B.C.E.—Ezra 1:1-4; 3:1-6. >>
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Insight, Vol. 1, p. 458
<< Another date that can be used as a pivotal point is the year 539 B.C.E., supported by various historical sources as the year for the overthrow of Babylon by Cyrus the Persian. (Secular sources for Cyrus’ reign include Diodorus, Africanus, Eusebius, and Ptolemy, as well as the Babylonian tablets.) >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
The Watchtower, May 15, 2003, p. 4
<< One pivotal date is 539 B.C.E., the year when Persian King Cyrus overthrew Babylon. Secular sources for the time of his reign include Babylonian tablets and documents of Diodorus, Africanus, Eusebius, and Ptolemy. >>
Quoted above, but here it is again:
The Watchtower, May 15, 1971, p. 316
Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. 
And finally we have the Society's authoritative and more detailed statement summarizing the above information:
Insight, Vol. 1, pp. 452-453
<< Babylonian Chronology. Babylon enters the Biblical picture principally from the time of Nebuchadnezzar II onward. The reign of Nebuchadnezzar’s father Nabopolassar marked the start of what is called the Neo-Babylonian Empire; it ended with the reigns of Nabonidus and his son Belshazzar and the overthrow of Babylon by Cyrus the Persian. This period is of great interest to Bible scholars since it embraces the time of the Babylonian destruction of Jerusalem and the greater part of the 70-year period of Jewish exile.
Jeremiah 52:28 says that in the seventh year of Nebuchadnezzar (or Nebuchadrezzar) the first group of Jewish exiles was taken to Babylon. In harmony with this, a cuneiform inscription of the Babylonian Chronicle (British Museum 21946) states: “The seventh year: In the month Kislev the king of Akkad mustered his army and marched to Hattu. He encamped against the city of Judah and on the second day of the month Adar he captured the city (and) seized (its) king [Jehoiachin]. A king of his own choice [Zedekiah] he appointed in the city (and) taking the vast tribute he brought it into Babylon.” (Assyrian and Babylonian Chronicles, by A. K. Grayson, 1975, p. 102; compare 2Ki 24:1-17; 2Ch 36:5-10.) (PICTURE, Vol. 2, p. 326) For the final 32 years of Nebuchadnezzar’s reign, there are no historical records of the chronicle type except a fragmentary inscription of a campaign against Egypt in Nebuchadnezzar’s 37th year.
For Awil-Marduk (Evil-merodach, 2Ki 25:27, 28), tablets dated up to his second year of rule have been found. For Neriglissar, considered to be the successor of Awil-Marduk, contract tablets are known dated to his fourth year.
A Babylonian clay tablet is helpful for connecting Babylonian chronology with Biblical chronology. This tablet contains the following astronomical information for the seventh year of Cambyses II son of Cyrus II: “Year 7, Tammuz, night of the 14th, 1 2⁄3 double hours [three hours and twenty minutes] after night came, a lunar eclipse; visible in its full course; it reached over the northern half disc [of the moon]. Tebet, night of the 14th, two and a half double hours [five hours] at night before morning [in the latter part of the night], the disc of the moon was eclipsed; the whole course visible; over the southern and northern part the eclipse reached.” (Inschriften von Cambyses, König von Babylon, by J. N. Strassmaier, Leipzig, 1890, No. 400, lines 45-48; Sternkunde und Sterndienst in Babel, by F. X. Kugler, Münster, 1907, Vol. I, pp. 70, 71) These two lunar eclipses can evidently be identified with the lunar eclipses that were visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E. (Oppolzer’s Canon of Eclipses, translated by O. Gingerich, 1962, p. 335) Thus, this tablet points to the spring of 523 B.C.E. as the beginning of the seventh year of Cambyses II.
Since the seventh year of Cambyses II began in spring of 523 B.C.E., his first year of rule was 529 B.C.E. and his accession year, and the last year of Cyrus II as king of Babylon, was 530 B.C.E. The latest tablet dated in the reign of Cyrus II is from the 5th month, 23rd day of his 9th year. (Babylonian Chronology, 626 B.C.–A.D. 75, by R. Parker and W. Dubberstein, 1971, p. 14) As the ninth year of Cyrus II as king of Babylon was 530 B.C.E., his first year according to that reckoning was 538 B.C.E. and his accession year was 539 B.C.E. >>
Note that all of the above material proves that the Watchtower Society agrees that Cyrus' accession year began about October 539 BCE, and his 1st regnal year began Nisan 1, 538 BCE.
The poster "ScholarJW" has vaguely implied that in some unspecified way the rule of Darius the Mede must be fit in with that of Cyrus. Obviously, the Society disagrees, since it says nothing about Darius the Mede in any of the above material. In some older Watchtower publications the identity of Darius the Mede is discussed, but in no case does that change the dates for Cyrus' reign.
I hope this material provides some useful source material for our astute posters.

Several of our less enlightened posters have made claims that are quite ridiculous, and indicate a nearly complete lack of familiarity with what they're talking about. Arauna, for example, focuses on the vague notion -- which she never explains coherently -- that the Greek Olympiads are somehow a better source for dating the reign of Cyrus the Great than are astronomical tablets in conjunction with Persian contract tablets and other contemporary documents. But the Watchtower Society disagrees, as I will now show.
Watchtower publications contain several mentions of the Greek Olympiads, such as these:
Insight, Vol. 1, p. 447
<< The Greeks figured time by means of four-year periods called Olympiads, starting from the first Olympiad, calculated as beginning in 776 B.C.E. Additionally, they often identified specific years by referring to the term of office of some particular official. >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
Note that the Greek historian Diodorus Siculus is referenced as the source of the statements about the Olympiads.
A question that arises is, How reliable are the histories of Diodorus Siculus? Note what the Watchtower Society had to say about these:
The Watchtower, April 1, 1969, pp. 222-223
<< But what about the later historians of the Greeks and the Romans? Do they supply chronology that is sufficiently exact that it poses a serious challenge to the Bible’s record? Among them we may consider Diodorus Siculus (1st century B.C.E.). Of the original forty books of his history, only fifteen have come down to us. Five of these deal with the mythic history of Egypt, Assyria, Ethiopia and Greece, and the remainder chronicle the second Persian war and extend to the time of Alexander the Great’s successors. It is said of Diodorus that “he has been at little pains to sift his materials, and hence frequent repetitions and contradictions may be found in the body of the work. . . . In the chronology of the strictly historical period he is occasionally inaccurate.”—The Encyclopædia Britannica, 9th edition, Volume 7, page 245. >>
So the Society itself argues that Diodorus' histories must be taken with a good grain of salt.
Nevertheless, any ancient source like Diodorus can be quite accurate in its chronology. Diodorus, it turns out, is accurate for at least the period in question here, 539 BCE through about 485 BCE. Note what the Society said about how Diodorus' dating by Olympiads matches up with dating by various other ancient documents:
The Watchtower, May 15, 1971, p. 316
<< Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. >>
Next note what the Insight book had to say about this:
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Pretty much the same as the above 1971 Watchtower said.
However, this description of the evidence for 539 BCE was incomplete (more complete information was given on page 453). Another Watchtower publication also gave more complete information:
The Watchtower, October 1, 2011, p. 28
<< A PIVOTAL DATE IN HISTORY
The date 539 B.C.E. when Cyrus II conquered Babylon is calculated using the testimony of:
Ancient historical sources and cuneiform tablets: Diodorus of Sicily (c. 80-20 B.C.E.) wrote that Cyrus became king of Persia in “the opening year of the Fifty-fifth Olympiad.” (Historical Library, Book IX, 21) That year was 560 B.C.E. The Greek historian Herodotus (c. 485-425 B.C.E.) stated that Cyrus was killed “after he had reigned twenty-nine years,” which would put his death during his 30th year, in 530 B.C.E. (Histories, Book I, Clio, 214) Cuneiform tablets show that Cyrus ruled Babylon for nine years before his death. Thus, nine years prior to his death in 530 B.C.E. takes us back to 539 B.C.E. as the year Cyrus conquered Babylon.
Confirmation by a cuneiform tablet: A Babylonian astronomical clay tablet (BM 33066) confirms the date of Cyrus’ death in 530 B.C.E. Though this tablet contains some errors regarding the astronomical positions, it contains the descriptions of two lunar eclipses that the tablet says occurred in the seventh year of Cambyses II, the son and successor of Cyrus. These are identified with lunar eclipses visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E., thus pointing to the spring of 523 B.C.E. as the beginning of Cambyses’ seventh year. That would make his first regnal year 529 B.C.E. So Cyrus’ last year would have been 530 B.C.E., making 539 B.C.E. his first year of ruling Babylon. >>
Note clearly that the second point uses astronomical dating to arrive at 539 BCE for the first year of Cyrus' ruling Babylon: Two eclipses, 523 and 522 BCE, point to the 7th year of Cambyses, so his 1st year was 529, and the 9th year of his predecessor Cyrus was 530 BCE, thus arriving at 538 BCE as Cyrus' 1st year, and 539 as his accession year (counted as year zero in the Babylonian dating system).
Thus, this 2011 Watchtower article was forced to admit that a contemporary Persian astronomical tablet, along with cuneiform documents and contract tablets that establish that Cambyses reigned for seven years and Cyrus reigned for nine years, solidly point to the date that the Watchtower Society uses as "a pivotal date in history".
Also note that the above Watchtower material admits that the Royal Canon of Ptolemy accurately shows the fall of Babylon in 539 BCE.
That these sources all converge on 539 BCE as the date of Babylon's overthrow is agreed to in the following Watchtower material:
All Scripture Is Inspired, pp. 282-283
<< 28 Pivotal Date for the Hebrew Scriptures. A prominent event recorded both in the Bible and in secular history is the overthrow of the city of Babylon by the Medes and Persians under Cyrus. The Bible records this event at Daniel 5:30. Various historical sources (including Diodorus, Africanus, Eusebius, Ptolemy, and the Babylonian tablets) support 539 B.C.E. as the year for the overthrow of Babylon by Cyrus. The Nabonidus Chronicle gives the month and day of the city’s fall (the year is missing). Secular chronologers have thus set the date for the fall of Babylon as October 11, 539 B.C.E., according to the Julian calendar, or October 5 by the Gregorian calendar.
29 Following the overthrow of Babylon, and during his first year as ruler of conquered Babylon, Cyrus issued his famous decree permitting the Jews to return to Jerusalem. In view of the Bible record, the decree was likely made late in 538 B.C.E. or toward the spring of 537 B.C.E. This would give ample opportunity for the Jews to resettle in their homeland and to come up to Jerusalem to restore the worship of Jehovah in “the seventh month,” Tishri, or about October 1, 537 B.C.E.—Ezra 1:1-4; 3:1-6. >>
Insight, Vol. 1, p. 454
<< The date of 539 B.C.E. for the fall of Babylon can be arrived at not only by Ptolemy’s canon but by other sources as well. The historian Diodorus, as well as Africanus and Eusebius, shows that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/559 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/530 B.C.E.). Cuneiform tablets give Cyrus a rule of nine years over Babylon, which would therefore substantiate the year 539 as the date of his conquest of Babylon.—Handbook of Biblical Chronology, by Jack Finegan, 1964, pp. 112, 168-170; Babylonian Chronology, 626 B.C.–A.D. 75, p. 14; see comments above under “Babylonian Chronology,” also PERSIA, PERSIANS. >>
Insight, Vol. 1, p. 458
<< Another date that can be used as a pivotal point is the year 539 B.C.E., supported by various historical sources as the year for the overthrow of Babylon by Cyrus the Persian. (Secular sources for Cyrus’ reign include Diodorus, Africanus, Eusebius, and Ptolemy, as well as the Babylonian tablets.) >>
Insight, Vol. 1, p. 566
<< Cyrus succeeded his father Cambyses I to the throne of Anshan, which was then under the suzerainty of the Median king Astyages. Diodorus (first century B.C.E.) places the start of Cyrus’ reign in the first year of the 55th Olympiad, or 560/559 B.C.E. >>
The Watchtower, May 15, 2003, p. 4
<< One pivotal date is 539 B.C.E., the year when Persian King Cyrus overthrew Babylon. Secular sources for the time of his reign include Babylonian tablets and documents of Diodorus, Africanus, Eusebius, and Ptolemy. >>
Quoted above, but here it is again:
The Watchtower, May 15, 1971, p. 316
Other sources, including Ptolemy’s canon, point to the year 539 B.C.E. as the date for Babylon’s fall. For example, ancient historians such as Diodorus, Africanus and Eusebius show that Cyrus’ first year as king of Persia corresponded to Olympiad 55, year 1 (560/59 B.C.E.), while Cyrus’ last year is placed at Olympiad 62, year 2 (531/30 B.C.E.). (The years of the olympiads ran from approximately July 1 to the following June 30.) Cuneiform tablets give Cyrus a rule of nine years over Babylon. This would harmonize with the accepted date for the start of his rule over Babylon in 539 B.C.E.
Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. 
And finally we have the Society's authoritative and more detailed statement summarizing the above information:
Insight, Vol. 1, pp. 452-453
<< Babylonian Chronology. Babylon enters the Biblical picture principally from the time of Nebuchadnezzar II onward. The reign of Nebuchadnezzar’s father Nabopolassar marked the start of what is called the Neo-Babylonian Empire; it ended with the reigns of Nabonidus and his son Belshazzar and the overthrow of Babylon by Cyrus the Persian. This period is of great interest to Bible scholars since it embraces the time of the Babylonian destruction of Jerusalem and the greater part of the 70-year period of Jewish exile.
Jeremiah 52:28 says that in the seventh year of Nebuchadnezzar (or Nebuchadrezzar) the first group of Jewish exiles was taken to Babylon. In harmony with this, a cuneiform inscription of the Babylonian Chronicle (British Museum 21946) states: “The seventh year: In the month Kislev the king of Akkad mustered his army and marched to Hattu. He encamped against the city of Judah and on the second day of the month Adar he captured the city (and) seized (its) king [Jehoiachin]. A king of his own choice [Zedekiah] he appointed in the city (and) taking the vast tribute he brought it into Babylon.” (Assyrian and Babylonian Chronicles, by A. K. Grayson, 1975, p. 102; compare 2Ki 24:1-17; 2Ch 36:5-10.) (PICTURE, Vol. 2, p. 326) For the final 32 years of Nebuchadnezzar’s reign, there are no historical records of the chronicle type except a fragmentary inscription of a campaign against Egypt in Nebuchadnezzar’s 37th year.
For Awil-Marduk (Evil-merodach, 2Ki 25:27, 28), tablets dated up to his second year of rule have been found. For Neriglissar, considered to be the successor of Awil-Marduk, contract tablets are known dated to his fourth year.
A Babylonian clay tablet is helpful for connecting Babylonian chronology with Biblical chronology. This tablet contains the following astronomical information for the seventh year of Cambyses II son of Cyrus II: “Year 7, Tammuz, night of the 14th, 1 2⁄3 double hours [three hours and twenty minutes] after night came, a lunar eclipse; visible in its full course; it reached over the northern half disc [of the moon]. Tebet, night of the 14th, two and a half double hours [five hours] at night before morning [in the latter part of the night], the disc of the moon was eclipsed; the whole course visible; over the southern and northern part the eclipse reached.” (Inschriften von Cambyses, König von Babylon, by J. N. Strassmaier, Leipzig, 1890, No. 400, lines 45-48; Sternkunde und Sterndienst in Babel, by F. X. Kugler, Münster, 1907, Vol. I, pp. 70, 71) These two lunar eclipses can evidently be identified with the lunar eclipses that were visible at Babylon on July 16, 523 B.C.E., and on January 10, 522 B.C.E. (Oppolzer’s Canon of Eclipses, translated by O. Gingerich, 1962, p. 335) Thus, this tablet points to the spring of 523 B.C.E. as the beginning of the seventh year of Cambyses II.
Since the seventh year of Cambyses II began in spring of 523 B.C.E., his first year of rule was 529 B.C.E. and his accession year, and the last year of Cyrus II as king of Babylon, was 530 B.C.E. The latest tablet dated in the reign of Cyrus II is from the 5th month, 23rd day of his 9th year. (Babylonian Chronology, 626 B.C.–A.D. 75, by R. Parker and W. Dubberstein, 1971, p. 14) As the ninth year of Cyrus II as king of Babylon was 530 B.C.E., his first year according to that reckoning was 538 B.C.E. and his accession year was 539 B.C.E. >>
Note that all of the above material proves that the Watchtower Society agrees that Cyrus' accession year began about October 539 BCE, and his 1st regnal year began Nisan 1, 538 BCE.
The poster "ScholarJW" has vaguely implied that in some unspecified way the rule of Darius the Mede must be fit in with that of Cyrus. Obviously, the Society disagrees, since it says nothing about Darius the Mede in any of the above material. In some older Watchtower publications the identity of Darius the Mede is discussed, but in no case does that change the dates for Cyrus' reign.
I hope this material provides some useful source material for our astute posters.

Let me try to lay this out for you (although this is more for any interested readers' benefit than for yours). The stars, planets, and Moon are components in a giant sky-clock that keeps perfect time. The 'fixed' stars are like the numbers spaced out on the clock's face. The planets and Moon are like the hands on the clock. Through their cyclical alignments with each other and against the 'fixed' starry backdrop, we can tell the time - the year, the month, the day.
Now, to be a 'competent' astrologer in ancient times, you had to be a competent astronomer. You had to interpret what you saw rather than what you wished you had seen. A bad astrologer would lose his job (or his life) if he faked his observations and his report to the court. It was a serious business involving years of rigorous training from childhood (remember Daniel?).
Not only that, but the Babylonians depended on genuinely dated observations over centuries to develop their mathematical astronomy/'science' that was eventually passed on to the Greeks and built upon by others. How were those observations dated? They used their calendar, i.e. the name and regnal year of the current ruler, the month, the day, even the time of night the observation took place. Any astrological interpretations coming from those observations have no bearing on the veracity of the celestial phenomena they witnessed.
So, when there is a dated astronomical text, we can check those observations, pin them to a BCE date, and hey presto! we can know in modern calendar terms when a king ruled. Thus, the 'stars' are reliable tools for dating kings' reigns.

Most of what CC says is just bluster he finds randomly, evidently by Googling key words. And if it he doesn't quite understand it, he must think others won't understand it either, and therefore he thinks it might impress people. He has pretty much proven that it is almost all fake blustering with him. More than half the time when he adds quotes from some secular reference, or displays a book cover with an impressive title, the source actually give evidence against his theories. To me that indicates that he couldn't have read or understood the sources he quotes from. Otherwise, that would indicate that he is just plain dishonest, so I prefer to think that he just doesn't understand most of what he reads.
Also, if CC was right that these eclipse calculations are not right unless you use his own more stable basis for calculating them, then he is rejecting the very ones that the Insight book uses that will ultimately give you 539 BCE for Cyrus conquering Babylon. I know that because the software I am using gives me exactly 539 BCE for Cyrus and exactly 587 BCE, instead of 607 BCE for the 18th year of Nebuchadnezzar, for example. He probably doesn't realize that if a new calculation was off for Nabonidus or Nebuchadnezzar by even one year, then Cyrus is also off by one year. If Nebuchadnezzar is off by 20 years, then Cyrus is also off by 20 years. You can't get around that.

You've already proved it. Look in the mirror.
Bullshit. Give some examples. If you dare.
Which you are obviously too stupid to understand. You are apparently going on obsolete Watchtower writings from more than 50 years ago.
You're not describing "bible chronology" but Watchtower chronology. And it was thoroughly debunked decades ago.
Tell that to the writers of the Insight book.
Bullshit. 
The dating was used to make the predictions, you moron!
So?
LOL! Such abysmal ignorance.

And how do you think the date is confirmed, you moron?

I've rarely seen anyone so clueless who could manage to work a computer keyboard and not stub a toe.
Once again, you moron: THERE ARE NO BIBLICAL DATES WITHOUT FIRST HAVING SECULAR DATES.
And you've not given any such "biblical dates", nor evidence for what you think they are.

Oh? What are the additional proofs?
Uh oh. A request for evidence. Run for the hills!

You want blood out of a stone?