Jewish communities appeared in southern Europe as early as the third century BCE, in the Aegean Islands, Greece, and Italy. Jews migrated to southern Europe from the Middle East voluntarily for opportunities in trade and commerce. Following Alexander the Great's conquests, Jews migrated to Greek settlements in the Eastern Mediterranean, spurred on by economic opportunities. Jewish economic migration to southern Europe is also believed to have occurred during the Roman era. Regarding Jewish settlements founded in southern Europe during the Roman era, E. Mary Smallwood wrote that "no date or origin can be assigned to the numerous settlements eventually known in the west, and some may have been founded as a result of the dispersal of Palestinian Jews after the revolts of AD 66–70 and 132–135, but it is reasonable to conjecture that many, such as the settlement in Puteoli attested in 4 BC, went back to the late republic or early empire and originated in voluntary emigration and the lure of trade and commerce." In 63 BCE, the Siege of Jerusalem saw the Roman Empire conquer Judea, and thousands of Jewish prisoners of war were brought to Rome as slaves. After gaining their freedom, they settled permanently in Rome as traders. It is likely that there was an additional influx of Jewish slaves taken to southern Europe by Roman forces after the capture of Jerusalem by the forces of Herod the Great with assistance from Roman forces in 37 BCE. It is known that Jewish war captives were sold into slavery after the suppression of a minor Jewish revolt in 53 BCE, and some were probably taken to southern Europe.