Greg,
If 606/605 was the year Daniel was taken captive, and if 537/536 was the year the Israelites returned, then their return took place in the 70th year.
Where we get messed up is using 605 and 537. It looks like a shorter period when it really is 70 years inclusively.
Jeremiah said that after 70 years God would punish the king of Babylon, and that the nations would serve the king of Babylon 70 years. These points aren't thought about too much. Usually we just look at the 70 years captivity.
Cyrus took Babylon on Oct. 29, a little after the first of the year. Thus the city was taken in 539/538. There then should be some significance, I think, in the year 608/607.
Daniel went to school 3 years. Then, in the king's 2nd year, he interpreted the dream about the image. If his 1st year of school was the king's accession year, and if his 2nd year was the king's 1st year, then his 3rd year would be the king's 2nd year of reign. Thus we have an indication that accession-year reckoning is in order. Additional evidence from the Jews in Elephantine indicate that we should also use this form of reckoning when calculating Artaxerxes' reign.
Unlike today's historians, PK 523 and 556 says that Cyrus was King Darius' general when Babylon was conquered, not the reigning king.
We know from Dan. 9:1-2 that Darius reigned at least a year. So if 539/538 was his accession ear, then 538/537 was his 1st year.
If he died that year, then Cyrus' accession year would finish out that year, and his 1st year would begin the fall of 537. The Jews could then begin their journey the following spring in 536.
A lot of "if's," but the best we can do is come up with if's.
Regarding the start date, the 37th year of Nebuchadnezzar is astronomically fixed by a tablet as being 568/567 spring to spring. That would make his accession year 605/604 spring to spring.
Since Nabopolassar died in August and Nebuchadnezzar came to the throne on Elul 1, the 6th month, we have an interesting situation. In a fall to fall calendar his first year would begin the fall of 605, making his accession year 606/605 fall to fall. In a spring to spring calendar his first year would begin the spring of 604, making 605/604 his accession year spring to spring.
I point this out in order to emphasize that the correct start date is 606/605 fall to fall, not 605/604 spring to spring.
That the Hebrews of this era sometimes used a fall to fall calendar when calculating the reigns of kings who used a spring to spring year is evidenced in Neh. 1.
Does this help? Email me if you need more info, but this is about the extent of my knowledge.
