One of the commonest assumptions underlying the academic study of the Jewish communities of the Graeco-Roman world is the certainty of Jewish ethnic continuity in diaspora settings. Ancient Jews, according to this line of thought, were committed to an ancestral heritage that ensured their separation from non-Jews and, with a few minor exceptions, secured the continuity of Jewish existence even outside the Jewish homeland. 1 This model, which is clearly based on the experiences of the mediaeval Jewish diaspora, often determines the ways in which the fragmentary evidence for the ancient Jewish diaspora is collected, analysed, and presented. The purpose of this chapter is to challenge this model, based as it is on a diachronic analysis of Jewish history, by positing an alternative model, based on a synchronic examination of the diasporic experiences of some of the Jews' closest neighbours. Given the limitations of time and space, the examination of the evidence will be far from complete, and will focus mainly on the Jews of the Egyptian chora. But even this brief sketch should suffice to demonstrate that Jewish continuity in diaspora settings cannot be taken for granted, and that in some cases it may have been the exception, not the rule.
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Our first stop is Thessalian Demetrias, founded by Demetrius Poliorcetes c. 290 BCE as a synoecism of several townlets. As its epigraphic remains reveal, this 'urbs valida et ad omnia opportuna' (Livy, 39.23.12) attracted many foreigners, including people from all over the Greek world and from various northern and western nations, as well as numerous Orientals - from the Phoenician cities, from Apollonia (Arsuf), Ascalon, and Gaza, from Carthage,
1 For different formulations of this assumption in recent scholarship see, e.g., Goudriaan 1988:12; Feldman 1993:66; Mélèze Modrzejewski 1995:87. A similar assumption pervades the study of ancient Jewish demography, for which see Brian McGing's chapter in this volume.