The Babylonian Talmud
By contrast, the Jewish community in Babylon was much more prosperous and stable. They could afford to take their time in adding commentary to the Mishna. Hence, the Babylonian Talmud, or Talmud Bavli, was not completed until the beginning of the sixth century and consisted of two and a half million words. This work was more polished and extensive than its Jerusalem counterpart, and it is in wider use today.
One of the reasons for the stability of the Jewish community in Babylon was that country had been governed by the Persian Sassanian dynasty since the third century. During this period, the official head of the Jewish community, the exilarch, established rabbinic academies in central Babylon.
As many as 1,200 scholars gathered at the academy in Sura that was founded by Rabbi Abba Ben Ibo (known as the Rav). By and large, these rabbis considered themselves as the repository of the strictest Jewish tradition. Consequently, the Babylonian Talmud is much more detailed than the Jerusalem Talmud.
However, this is not to say the undertaking did not face obstacles. During the years 455–475, before the sages could finish the project, most synagogues and academies were closed by the authorities. The repression was prompted by the Persian priests who were growing anxious over the encroaching Christian missionaries, and the reaction also extended to the Jewish community. However, the Jewish institutions were re-established by 500, and shortly thereafter, the Babylonian Talmud was completed.