In 1270 The Catalan monk Raymundus Martine wrote the name Jehova....in his book PUGIO FIDEI, this is the oldest found version of the name of Jehovah, complete with vowels inserted.
Raymundus Martini was an expert on the Hebrew and Latin languages, and was acquainted with the Jewish scriptures.
The Hebrew name of God with only the vowels JHVH, (note that both V and W were used in Hebrew) dates from UR of the Chaldeans, where archaeologist Delitszch found a cuneiform tablet with the name of God, on the Hebrew related. The origin of that clay tablet must have been about 2200 BC. So in ancient Babylon the name of Yahve or Jehovah, the later God of the Israelites, was already known at that time. (source: The way of humanity part 1, p, 137 Dr. A. Halberstadt 1909)