Since the time of the Roman Empire, Jewish people have constituted a significant, economically important population of non-Christians in a continent in which very specific versions of Christianity were the compulsory state religion and religious non-conformity was frequently persecuted. As such, their social and legal status varied considerably but was always extremely precarious.
The ancient Greeks were anti-Semitic when Rome was a republic, not an empire. And the Egyptians earlier than that. I think it has to do with their separation from other cultures, which God commanded them to do. No one likes people who won't conform to their ideas of what is right.
Maybe, but anti-Semitism in Europe today doesn't have much to do with the Ancient Greeks or Egyptians.
I'm not sure that's true anyway. The Egyptians certainly warred with Israel, but they warred with everybody. Solomon married an Egyptian princess, a prayer written by her praising her husband is in Psalms. Later there was a movement of Greeks attracted by the idea of monotheism[0 Historical background, third paragraph] that used to hang out near Synagogues and debate philosophy with Rabbis. In fact it's arguably this which made adoption of Christianity by Greeks so easy and rapid, kickstarting Christianity.
There's also other evidence of Jews living perfectly peaceably and integrating well into other middle-eastern cultures. For example the corpus of incantation bowls[1] used by members of many different religious groups, but interestingly often created by Jewish scribes for non-Jewish clients.
So I don't think there's much evidence for Jewish people being picked out in this way in the pre-Roman and pre-Medieval world.
