Judean Chronology
This section will look at the chronology of the Kingdom of Judah before and up to the destruction of Jerusalem by Nebuchadnezzar II. The goal is to answer the second question - why is there is a dispute between the 587 BC and 586 BC dates for the destruction of Jerusalem?
The answer is that are discrepancies or ambiguities within the Bibles' chronology that make it difficult to determine precisely whether the destruction took place in the 18th or 19th regnal year of Nebuchadnezzar, and since it is only through the reign of Nebuchadnezzar that historians are able to date the events on the Julian calendar, it means we cannot be certain if the destruction took place in 586 or 587 BC. As explained by Young [1, p. 21]:
The Babylonian records describing the destruction of Jerusalem by the army of Nebuchadnezzar have not been found. As a consequence, all dates for that event must be derived from the scriptural record, as tied to the last events prior to the destruction that are described in the Babylonian archives. These are the Battle of Carchemish in 605 bc and the initial capture of the city and its ruler Jehoiachin in the spring of 597 bc.1 The time between the earlier of these two events and the final destruction of Jerusalem was less than twenty years. Since the period is fairly well documented in the Scriptures, it might be expected that it would not be difficult to establish the year in which the city was destroyed and the Babylonian Exile began.
Such, however, has not been the case. Although the Scriptures state that the end came in the fourth month of the eleventh year of Zedekiah, scholars are divided on whether this refers to 586 bc or 587 bc. Jeremy Hughes listed eleven scholars who preferred the first date and eleven who preferred the second.2 Edwin Thiele was among those preferring 586, and this seems to be the date most widely used in the popular literature. However, to Hughes’s list of those favoring 587 should be added the names of Donald Wiseman and Kenneth Kitchen.
References
[1] R. C. Young, “When Did Jerusalem Fall?” Journal of the Evangelical Theological Society, vol. 47, no. 1, p. 21, 2004, [Online]. Available: http://www.rcyoung.org/articles/jerusalem.pdf.