QC: 2520 years is a total scam. Judea's desolation began in 587 BC, not 607BC. Get up to speed download Gentile Times Reconsidered.
COJ in GTR takes the popularist's view of the ancient timeline wherein 587 BCE reflects the 18th year of Nebuchadnezzar II, the date they assign to the fall of Jerusalem.
The WTS, of course, seem to have focussed on 539 BCE as the "pivotal date" in ancient history that they consider uniquely reliable. Many other dates they dismiss as "revised" dates in ancient history. So first note, that 539 BCE is part of the secular timeline that dates the 18th of Nebuchadnezzar II to 587 BCE and the 20th of Artaxerxes to 445 BCE.
The WTS uses the Bible's reference to a 70-year exile and desolation period of sabbath rest at 2 Chronicles 36:21. Thus they add 70 years to 537 BCE, the year they date the return and get 607 BCE as the year Jerusalem falls. By contrast the secular history would reflect this same period as only 50 years (i.e. 587-537 BCE).
To make the "70 weeks" prophecy work, which clearly must begin in 455 BCE, the WTS rejects the 445 BCE date for the 20th of Artaxerxes, use archaeology to prove a co-rulership between Xerxes and Darius I, and overlap 10 years of Xerxes and Darius I to move the date for the 20th of Artaxerxes back in time 20 years from 445 BCE back to 455 BCE. Then, to get back on track with the secular timeline, they add those 10 years back during the reign of Artaxerxes I, which makes his rule 51 years instead of 41 years, using two extant texts dated to year 51 of Artaxerxes! These texts are considered "spurious" or alternative by COJ but they are there!
Which timeline is reliable?
In the meantime, you have other issues! For instance, even COJ considers the simple reading of the "70 weeks" prophecy to point to Cyrus fulfilling thta prophecy! How obvious can it get? The prophecy begins with the "word that goes forth to rebuild Jerusalem" and the beginning of the work to rebuild Jerusalem is dated in month 7 in the 1st of Cyrus. So some reading the Bible, such as Martin Anstey, feel as though there is a direct conflict between the Bible and this part of the secular timeline. That is, Martin Anstey also dates the "70 weeks" as beginning in 455 BCE but dates that event to the 1st of Cyrus rather than the 20th of Artaxerxes.
Chronologists also note something else, particularly in comparison to COJ, which is the 70 years of desolation per Josephus is dated from the lst deportation down to the 1st of Cyrus. That's a direct secular contradiction between the Jewish timeline for the NB Period and the current secular records, which all come from the Persian Period.
So is 587 BCE a truly reliable date for the 18th of Nebuchadnezzar II? If you date the 1st of Cyrus to 455 BCE and follow Josephus by adding 70 years, then 525 BCE would date year 23 of Nebuchadnezzar II. But at this point we find an incredible coincidence. COJ promotes the astrotext called the "VAT4956" as the most important ancient document for chronology. In this text, the majority of the planetary observations clearly are dated to 568 BCE for year 37 of Nebuchadnezzar II. This agrees with year 18 falling in 587 BCE. But there were always two obvious "errors" in the text in Lines 3 and 14. Line 3 says the moon was 1 cubit in front of the "Rear Foot of the Lion" (GIR ar sa UR-A)(sigma-Leonis) on the 9th of Nisan. Hermann Hunger, who translated the text, notes this is an "error for the 8th"; that is, a day off. Then in Line 14, P.V. Neugebauer notes about a day's discrepancy for the Moon being 1 cubit away from beta-Virginis (MUL KUL sa TIL GIR UR-A) on the 5th of Sivan. Using a modern astronomical program, however, it turns out that these two lunar positions that are about a day off for 568 BCE, are exact matches for 511 BCE. Because of the exact match, it is not considered an "error" but an intentional insertion into the text. But why? Well, one obvious explanation is that the originators of the text are trying to hide a reference to another date for year 37 of Nebuchadnezzar II; obviously, the original dating.
At this point, those who compare 511 BCE with other timelines, note that this dating matches the same timeline you get when 455 BCE dates the 1st of Cyrus, and thus 525 BCE year 23 of Nebuchadnezzar II in 525 BCE. In that case, year 37 falls in 511 BCE!
Now at this point, you have no choice but to investigate possible secular revisionism for the NB and Persian Period in the secular records. That's because you now have Biblical harmony and secular harmony via the VAT4956 when you date the 1st of Cyrus to 455 BCE.
WHAT DOES THE PRELIMINARY INVESTIGATION SHOW?
Almost immediately you have little choice but to observe another critical contradiction between the secular timeline and the Bible, which is found at Ezra 6:14,15 with comparison to Daniel 11:2. These scriptures not only show that Darius I only ruled for 6 years, but that year 6 of Darius I was also the accession year of a king called "Artaxerxes" who was prophesied to wage a major compaign against Greece. That campaign was clearly the massive invasion of Greece by "Xerxes" at the time of the Battle of Salamis. Thus per the Bible, Xerxes and Artaxerxes I were the same king. If that's the case, then the 21-year by Xerxes must be combined with the 41-year reign by Artaxerxes, reducing the Persian timeline by 21 years. Further, if a fake 30 years were added to the reign of Darius I, perhaps to make him old enough to be the grandfather to "Artaxerxes" his alleged grandson vs. his son, then you reduce the timeline by 30 years. Thus right off the bat, if you want to follow the Bible, you automatically have to reduce the Persian timeline by 51 years. That means that 539 BCE is bogus along with 587 BCE as well as 607 BCE.
So anyone now still dating 587 BCE to any legitimate date in the current NB timeline are not up to date on all the issues, and are ignoring both the Bible and the VAT4956, both of which date year 37 to 511 BCE.
Now whether or not you follow this, clearly there are "choices" to be made and each must make their own choice. But there is absolutely no getting away from revisionism and a conflict between secular records like those of Josephus and the VAT4956 and other records coming down to us, like the "Babylonian Chronicle" which itself claims to be a copy from the 21st year of Darius (II).
You have to ask yourself, why does the VAT4956 hide two 511 BCE references in a text otherwise dated to 568 BCE for year 37 of Neb2, and why 511 BCE for year 37 coincidentally is the same dating you get when the 1st of Cyrus is dated to 455 BCE? Is this a coincidence or evidence of the original timeline?
CHOICES! But these choices should be "informed" choices!
