From the end of the Second Jewish Revolt and the Diaspora, around 130 AD, the Jews lived more or less quietly in various cities around the Roman and the Parthian Empires (and then the Sassanian Empire), and in the trading cities of the Arabian peninsula. It was probably because of the Diaspora that many Jews gave up farming and became traders. Many Jews learned Latin and Greek, and some gave up speaking Aramaic or Hebrew.
The general conversion of the Roman Empire to Christianity in the 300s AD, however, brought new problems to the Jews. Efforts to convert the last of the believers in Roman religion were accompanied by efforts to convert the Jews as well. Many Christians believed that if there was anyone near them who was not a good Christian, their own immortal souls were in danger of going to hell: they had a duty to convert everybody, and if they failed they might go to hell.
On the other hand, other Christians believed that the Jews were special to God and should be left alone, as long as they kept to themselves and didn't try to interfere with Christians. So the Jews were sometimes treated very badly, and other times less badly.