At first, as we have seen, the Rabbinical schools were founded on Jewish soil.

But Palestine did not continue to offer a friendly welcome.

Under the more tolerant rulers of Babylonia or Persia, Jewish learning found a refuge from the harshness experienced under those of the Holy Land.

The Babylonian Jewish schools in Nehardea, Sura, and Pumbeditha rapidly surpassed the Palestinian in reputation, and in the year 350 C.E., owing to natural decay, the Palestinian schools closed.
The Talmud is accordingly not one work, but two, the one the literary product of the Palestinian, the other, of the Babylonian _Amoraim_.

The latter is the larger, the more studied, the better preserved, and to it attention will here be mainly confined.