The timeline dates the last kings of Judah and the Babylonian exile using the conventional scholarly (astronomical) chronology, not the rabbinic Anno Mundi count of Seder Olam Rabbah. This page explains why, and how BCE dates for events recorded in Babylonian, Assyrian, and Hebrew sources are reconciled onto a single timeline.
Astronomical anchors
Ancient Near Eastern chronology is not free-floating — it is pinned to a handful of dateable astronomical events. Assyrian scribes kept eponym (limmu) lists, naming each year after an official rather than numbering it. One surviving list notes a solar eclipse during the eponymy of Bur-Sagale, identified with the eclipse of 15 June 763 BCE (the Assyrian eclipse), which is calculable from modern astronomy and independent of any human record-keeping. That single fixed point lets the whole Assyrian eponym sequence be dated year by year, both forward and backward.
Babylon supplies a second, overlapping anchor: centuries of astronomical diaries recording lunar and planetary positions alongside the regnal year of the reigning king. Tablets such as VAT 4956, dated to the 37th year of Nebuchadnezzar II, describe lunar and planetary positions precise enough to be matched to a single Julian year by modern retrocalculation — fixing Nebuchadnezzar's reign, and with it the Babylonian conquest of Jerusalem, to within a year. The 2nd-century astronomer Ptolemy later compiled these Babylonian regnal years into a continuous king list, the Canon of Kings, which still checks out against the diaries themselves.
Reconciling lunisolar calendars
Babylonian, Assyrian, and Hebrew calendars are all lunisolar: twelve lunar months drift out of step with the solar year, so an extra month is periodically intercalated to keep festivals in their proper season. Babylon and Judah both eventually settled into the same 19-year Metonic cycle of leap months, which is part of why Babylonian and Hebrew reckonings of a given year tend to agree once intercalation is accounted for. Regnal years add a further wrinkle: a king's first year could be counted from his accession or from the following new year (accession-year vs. non-accession-year reckoning), which alone can shift a date by one year between sources describing the same event.
Rome as a cross-reference
Rome enters this chronology later, but usefully: the historian Josephus, writing in the 1st century CE, synchronizes events from Judean history with dated Olympiads and Roman consular years, both of which are independently fixed relative to the Julian calendar and, eventually, the Anno Domini era. These synchronisms don't establish the 7th–6th century BCE dates themselves — the astronomical anchors above do that — but they provide an independent check that the accumulated regnal-year arithmetic from Babylon down to the Roman period hasn't quietly drifted.
The "missing years" question
Traditional rabbinic chronology, following Seder Olam Rabbah (2nd century CE), places the destruction of the First Temple about 166 years later than the astronomically-anchored date used here, and correspondingly compresses the Persian period into a much shorter span than Greek and Babylonian sources record. This discrepancy is often called the missing years problem. Both traditions deserve to be stated plainly rather than papered over: Seder Olam Rabbah's count underlies the Hebrew Anno Mundi calendar in religious use today, while the astronomical anchors above underlie the secular dates on this timeline. This site uses the latter because the eclipse and diary records are independently verifiable against modern astronomy, but the former remains the received tradition, and readers should know the two do not agree by a matter of centuries when the numbers are compared directly.