The history of the Alexandrian Jews dates from the foundation of the city by Alexander the Great, 332 BCE, at which they were present. They were numerous from the very outset, forming a notable portion of the city's population under Alexander's successors. The Ptolemies assigned them a separate section, two of the five districts of the city, to enable them to keep their laws pure of indigenous cultic influences. The Alexandrian Jews enjoyed a greater degree of political independence than elsewhere. While the Jewish population elsewhere throughout the later Roman Empire frequently formed private societies for religious purposes, or organized corporations of ethnic groups like the Egyptian and Phoenician merchants in the large commercial centers, those of Alexandria constituted an independent political community, side by side with that of the other ethnic groups.