The date of the Return indeed is the only possible date to end the seventy year period as descibed by Jeremiah, Daniel and Ezra. The other candidate, 539 BCE for the Fall of Babylon is impossible for the very simple amongst many others that the Jews were still Babylon at that time and the land was still desolate at that time.
You make good point, Scholar. However, this is old school and limited. Ezra 6:14,15 confirms two things:
1) That Darius I died in his sixth year.
2) That a king called "Artaxerxes" succeeded him that year and helped complete the temple.
When this was investigated it was discovered "Artaxerxes" was actually the second name for Xerxes and they were the same king. Xerxes claimed he was his own son to avoid an assasination attempt and further conflict with the Athens, which he had destroyed. The Jews liked Xerxes/Artaxerxes so went along with this counterintelligence against the Greeks, but then later the Persians paid off other Greek historians (i.e. Xenophon, Plato, Aristotle) to revise their history and thus the revised Persian-influenced Persian and Greek timelines became "official" in later times. Later, after Christianity, it seems to have been latched onto by Jews to help deny Christ or deflect from when Christ was to arrive. Thus the true date for the fall of Jerusalem and the true date of the Exodus are notoriously manipulated historical events in the academic world, which is only influenced by anti-Biblical academic societies. But we've past that now. Enough astronomical events have been left on the books to completely coordinate and reconstruct the original timeline, a timeline now augmented with advanced RC14 dating confirmation. So there's just no excuse to keep debating the 70 years as far as the absolute dates without addressing Ezra 6:14,15 and the Persian Period revisions.
YOU can ignore that part of the history if you want, but others of us have corrected the timeline and now see complete harmony between the secular and Biblical timelines.
Thus, at the end of the day, it is not a matter of anything being at all confusing any more. We know why secular and Biblical dates for the NB Period are discrepant. It's not a mystery any more. Those who pretend there are options still are simply ill informed. I've done my share by explaining how to correct the secular timeline, so that's as much as I can do. If my evidence is not acceptable then that's your choice. But I'm content with the results totally.
The second thing is this. A lot of the focus on getting the NB Period correct is really to see how that affects modern-day events, such as 1914 or 1992. However, 1914 and 1992 are past dates. Thus whether or not the messiah arrives in 1914 or 1992 are the primary interests in ancient chronology. But it also allows us to retrodate all events based upon modern events. For instance, 1947 fulfills the 70th week jubilee for the Jews and thus can be directly used to date the Exodus to 1386 BCE, because the two events are linked. Likewise, since we know when a 70-week period for the 1st coming ends in 36CE, we can confirm the dating for the entire week, including the year the 70 weeks begin in 455 BCE. The return of the Jews occurs on the 19th jubilee of the week, the Exodus is the 1st jubilee and 1947 is the 49th jubilee. So we can now use modern events to actually correct and compare to the ancient dates now. RC14 dating confirms the timeline along with several specific eclipses.
So all I can basically say is some of us out here are not experiencing contradiction between the Bible and secular history any more. We've resolved all the contradictions and have archaeological and astronomical and historical evidence in place supporting it. It's one thing to disagree with the conclusions but quite another to pretend there is no possible resolution when in fact it actually has been resolved.
So maybe I should consider myself lucky I don't have to deal with the contradictions any more. Yeah, exactly. Paint me HAPPY!