Even the extreme values were not very discordant--ranging from a minimum, for the creation of the earth, of 3761 BC in the Jewish calendar (still in use) to a maximum of just ofer 5500 BC for the Septuagint. Most calculators had reached a figure very close to Ussher's 4004. The Venerable Bede had estimated 3952 BC several centuries before, while J.J. Scaliger, the greatest scholar of the generation just before Ussher, had placed creation at 3950 BC. Thus, Ussher's 4004 was neither idiosyncratic nor at all unusual; it was, in fact, a fairly conventional estimate developed within a large and active commnity of scholars...
First of all, the date 4004 coordinates comfortably with the most important of chronological metaphors--the common comparison of the six days of God's creation with 6,000 years for the earth's potential duration: "but, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day" (2 Peter 3:8). Under this widely accepted scheme, the earth was created 4,000 years before the birth of Christ and could endure as much as 2,000 years thereafter (a proposition soon to be tested empirically and, we all hope, roundly disproved!)
Socrates told us to know ourselves, and no datum can be more important for humanism than an accurate chronology serving as a framework for the epic of our cultures, our strivings, our failures, and our hopes.