The 'oldest dated document of the Cairo Genizah' (Halper 331): The Seleucid era and sectarian Jewish calendars

Halper 331 is the fragment of a codex that has been styled the 'oldest dated document of the Cairo Genizah'. It preserves the opening of a Jewish legal document dated to the year 1182 (Seleucid era), which appears to have been copied into this codex, probably as a formulary, not long after this date, in the late 9th century. In this article, the text of this fragment, in Aramaic and Hebrew, is edited, and its identification as the beginning of a marriage contract (ketubbah) is evaluated. Its Egyptian provenance is questioned, partly because the earliest evidence for the introduction of the Seleucid era by Jews in Egypt dates from the mid-10th century. The article surveys the history of Jewish dating methods in early medieval Egypt and the Near East, in an attempt to clarify this question. The specific date of the document deviates from the rabbinic calendar, but agrees with that of the contemporary Jewish Near Eastern sectarian groups of Abū imrān al-Tiflīsī and Ismāīl al-Ukbarī; this document could thus uniquely attest one of these sectarian Jewish calendars.