It may come as a surprise to learn that the idea of a Christian Era dates back no future than the sixth century—A.D. It was a rather obscure Syrian monk named Dionysius Exiguus (Dennis the Little) who came up with it—and who miscalculated its “epoch” or starting point. His example was followed in the seventh century by the invention of a Moslem Era dating from the Hegira, the flight of Mohammed from Mecca to Medina in 622 A.D. Because the Moslem year is a lunar one and shorter than the solar year of the Christian calendar, as this book goes to press in 2002 A.D. the Moslem year has reached 1423 A.H. (Anno Hegirae), even though only 1,380 solar years have elapsed. In the eight century A.D., the Jets followed suit with an era of their own based on the “year of creation,” which according to tradition occurred in 3760 B.C. The Jewish year is a solar one, based on the moon but reconciled periodically with the solar year by means of leap-months, so its years keep pace with the Christian calendar. In 2002 A.D., the Jewish year is calculated 3760 + 2002 +5726.
Thus, early in the Middle Ages, the three great monotheistic faith began dating their own eras, and these usages now dominate the globe. But they were far from the first to introduce the idea of the era as such. Like many of our most essential modern institutions, the concept of the era dates back before modern times, indeed before medieval and classical times, all the way to the ancient Near East, the best documented area of the world for half of its recorded history. The story unfolded in two stages.
The immediate model for the religious eras was the Seleucid Era, which was used in the Mediterranean world from before the rise of the Roman Empire to well after its fall. It’s “epoch” was the (re-)conquest of Babylon by one of the successors of Alexander the Great, namely Seleucid I. In 312 B.C. Seleucid became the ruler of much of the Asian Near East, naming his son Antiochus I as co-regent late in his reign. Antiochus (and his descendants) continued to date by the years of Seleucus’s reign even after the latter’s death, and thus was born the novel idea of the dynastic era. It replaced the cumbersome system of starting a new era with the accession of each new king, which required memorizing the lengths of previous reigns (or written king lists) to calculate long-term contracts or to write history. So useful was the new idea that it soon spread beyond the borders of the Seleucid kingdom. Thus the dynastic Seleucid Era became a truly international era, sometimes known as the “Era of (all) the Greeks” (see the First Book of Maccabees 1:10).
But even the Seleucid Era had its limitations. After its introduction, the development of astronomy proceeded apace, led by such figures as Hipparchus in the second century B.C. and Ptolemy in the second century A.D. They required a system that went back before Alexander, and Ptolemy in particular provided one in the form of the “Era of Nabonassar.” Named for the king who ascended the throne of Babylon in 747 B.C. According to Berossos, a Babylonian priest writing in Greek in the third century B.C., Nabonassar was responsible for introducing a new historiography in Babylon. The question is, did Nabonassar introduce the era named for him, or was it a construct of later historians and astronomers? The fact that two other eras, both devised in the third century B.C., dated their epochs to the eighth century B.C. Supports the latter view. One of these was the Olympic Era, which was counted beginning with the first Olympiad in 776 B.C. The other was the Roman Era, dated “from the founding of Rome” (ab urbe condita), supposedly in 753 B.C.
But cuneiform records from Babylonia suggest otherwise. They show that numerous calendric reforms as well as innovations in chronological historiography, or what may be termed “chronograph,” do in fact go back to King Nabonassar. Among these are the so-called “Babylonian Chronicle,” a year-by-year record of major events affecting Babylonia and especially its priesthood; semi-annual “diaries” with observations of astronomical, meteorological and other natural phenomena (together with fluctuations in commodity prices), and occasionally historical events; and the regularization of the system of “intercalated new” of leap months—a system still largely adhered to by the Jewish calendar. So the possibility cannot be entirely ruled out that Nabonassar meant to introduce a new era beginning with his accession. True, political events frustrated his plans, for his son lost his throne to the Assyrians. But it is possible that astronomers continued to use the era, thus laying the groundwork for the later Seleucid Era and, ultimately, for our own era.
So, boys-and-girls, you see, it never was the Year of Our Lord until somewhere around 600 CE (current error -- yes, I mean, error).
Unfathomable Sea! whose waves are years,
Ocean of Time, whose waters of deep woe
Are brackish with the salt of human tears!
Thou shoreless flood, which in thy ebb and flow
Claspest the limits of mortality,
And sick of prey, yet howling on for more,
Vomitest thy wrecks on its inhospitable shore;
Treacherous in calm, and terrible in storm,
Who shall put forth on thee,
-- Percy Bysshe Shelley