Diaspora Jews “stood aside virtually completely” from the Jewish war of 66-70, writes Mary Smallwood in her Jews Under Roman Rule(356). By that, she means that Diaspora Jews didn’t send men or material to help their brothers in Judea,
She admits that “Possibly rather more help was offered than is admitted by Josephus, who is out to glorify the single-handed resistance of the province” (356), and her suspicion that Josephus is a biased witness is well-deserved.
But saying that the Diaspora didn’t rush to help with the war is not to say that the Diaspora was unaffected by events in the holy land: “Early in the war smouldering racial tension between Jews and Greeks in many Syrian cities flared up into mutually murderous attacks; immediately after the war attempts were made in Antioch and Alexandria to exploit the Jewish disgrace, while disturbances were stirred up among the Jews in Alexandria and Cyrenaica by extremist refugees from Judaea; and the universal exaction of the ‘Jewish tax,’ though not accompanied by any reduction in the religious liberty of the Diaspora, was a constant reminder of the destruction of the sanctuary which had been the focus of their religion” (357).
Jews were massacred and expelled from Caesarea, and Jews in Palestine responded with attacks on various cities with Jewish minorities: “Gaza, Ascalon, Ptolemais and Tyre on the coast, Philadelphia, Gerasa, Pella, Gadara, Hippos and Scythopolis in the Decapolis, and unspecified places in Gaulanitis” (357). They pillaged villagers and slaughtered Greeks. Greeks in Syria responded with further massacres on Jews (358). She observes that “the ferocity shown by both sides is evidence of long-standing mutual suspicion and dislike, which the collapse of Roman authority in the province of Judaea now gave an opportunity to satisfy” (358).