Should you want to do research, study the article by S.H. Horn & L.H. Wood, "The Fifth Century Jewish Calendar at Elephantine," published by the Journal of Near Eastern Studies in January, 1954. The authors propound that King Artaxerxes ascended to power about December, 465 BC. The authors use two papyrus to support their assumptions. Aramaic Papyrus No. 6, reads "Kislev 18 = Thoth [17], year 21, the beginning of the reign of Artaxerxes I."(1) The date of Thoth 17 shows the document was written after the Egyptian New Year. Since this document designates Thoth 17 as the ascension year of Artaxerxes I, then King Artaxerxes would have ascended to the throne after Thoth 1. If Artaxerxes ascended to the throne after Thoth 1, then the first year of Artaxerxes would have began a full year later. However, all the double dated papyri do not support the authors' assumptions.

Finally, the authors believe that most of the papyri support their position. The authors' assumptions are so great that they throw out several well preserved papyri by blaming the dating on Scribal errors. In contrast, a very careful study of all the Elephantine papyri shows that only one scribal error occurred in the papyri written during the reign of King Artaxerxes. Please read about scientific dating the Elephantine papyri to gain insight into the evidence from the 5th century BC.