 Like the Church of the East, the traditional center of the Manichaean church was in Seleucia-Ctesiphon.Mani dedicated his only Middle Persian writing, the Shāpuragān, to Shapur I.

Babylonia remained the center of Judaism in the world.The major book defining Rabbinic Judaism, the Babylonian Talmud, was written in Jewish Babylonian Aramaic in Asorestan between the 3rd and 5th centuries.