Anno Graecorum

The Seleucid era or Anno Graecorum (literally "year of the Greeks" or "Greek year"), sometimes denoted "AG", was a system of numbering years in use by the Seleucid Empire and other countries among the ancient Hellenistic civilizations. It is sometimes referred to as "the dominion of the Seleucidæ," or the Year of Alexander. The era dates from Seleucus I Nicator's re-conquest of Babylon in 312/11 BC after his exile in Ptolemaic Egypt, considered by Seleucus and his court to mark the founding of the Seleucid Empire. According to Jewish tradition, it was during the sixth year of Alexander the Great's reign (lege: not Alexander the Great, but his infant son, Alexander IV of Macedon) that they began to make use of this counting. The introduction of the new era is mentioned in one of the Babylonian Chronicles, the Chronicle of the Diadochi.

Two different uses were made of the Seleucid years:

These differences in the beginning of the year mean that dates may differ by one. Bickerman gives this example:

The Seleucid era was used as late as the 6th century AD, for instance in the Zebed inscription in Syria, dated the 24th of Gorpiaios, 823 (24 September, 512 AD), and in the writings of John of Ephesus. Syriac chroniclers continued to use it up to Michael the Syrian in the 12th century AD / 15th century AG. It has been found on Nestorian Christian tombstones from Central Asia well into the 14th century AD.

The Jewish / Babylonian calendar was used by Yemenite Jews until modern times, and continues to be used by them for certain ritual purposes even today.

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