Question on R. Yochanan's source: Maybe the years from the Exodus are counted from Iyar?

Answer: The verse considers the completion of the (Shemos 40,17) Mishkan in Nisan and the subsequent lifting of the cloud in Iyar (Bamidbar 10,11) to both be in the same (2nd) year. This shows that Iyar can't be the start of the new year.

Question: Maybe the years from the Exodus are counted from Sivan?

Answer: If so, the encampment at Sinai in Sivan would be dated as "the second year" in addition to "the third month". (Shemos 19,1)

Question: Maybe the years from the Exodus are counted from Tamuz, Av or Adar?

Source #2 (R. Elazar): The new year for kings is learned from a verse (Divrei ha'Yamim II 3,2) stating that Shlomo began building the Beis ha'Mikdash in Iyar, "in the second," which surely means that Iyar is second to the month from which the king's years are counted - namely, Nisan.

Question (Ravina): Maybe it means the second day of the month (Iyar)?

Answer: It would have said so explicitly.

Question: Maybe it means the second day of the week?

Answer: Firstly, the Torah does not speak in such terms. In addition, "in the second" is adjacent to "the second month". Therefore, it must also be referring to a month.

There is a Beraisa which supports R. Yochanan's source.

R. Chisda: Non-Jewish kings count years of reign from Tishrei

Source: One verse (Nechemyah 1,1) refers to Kislev of the 20th year and another verse (Nechemyah 2,1) refers to the subsequent Nisan as being in the 20th year of Artachshasta's reign.

Question: How do we know that the first verse is counting the years of Artachshasta's reign?

Answer (R. Papa): The identical phrase of "the twentieth year" in each verse creates a Gezeirah Shavah which proves that they are both counting the years of Artachshasta's reign.

Question: How do we know that the Kislev event preceded the Nisan event ? Maybe the Nisan event took place previously?

Answer: A Beraisa states that Chanani's message to Nechemyah in Kislev (Nechemyah 1,2-3) was repeated to the King in Nisan (Nechemyah 2,1-6).

Question (R. Yosef): A verse (Chagai 1,1) concerning the reign of Daryavesh refers to the month Elul of his second year, and another verse (Chagai 2,1) refers to the subsequent month of Tishrei without calling it "the third year"!

Answer (R. Avahu): Koresh was so called because he was a kosher king (switch "r" and"sh"); therefore his years are dated from Nisan, like a Jewish king.

Question #1 (R. Yosef): We find a verse (Ezra 6,15) that refers to Adar of the sixth year of the reign of Daryavesh, and another verse (Ezra 7,8) refers to the month of Av fifteen months later as being in the seventh year. If Nisan began the years of Daryavesh, it should have been dated as the eighth year!

Question #2 (R. Yosef): We are discussing Daryavesh, not Koresh!

Answer to question #2: Koresh, Daryavesh and Artachshasta are all the same person. He was named Koresh because he was a kosher king, Artachshasta was the name of his kingdom, and Daryavesh was his name.

Answer to question #1: His years were counted from Tishrei after he turned evil.

Question (R. Kahana): Did Daryavesh really turn evil? Surely we find that he gave many gifts to the Kohanim! (Ezra 6,9)