The teachings and traditions of the rabbis.
The rise of rabbinism was gradual.
It stretched back to the time of Esdras and Nehemiah, if not beyond it.
It is a synthesis of the opinions of Jewish scholars of the East and the West from the aforesaid probable date of origin to the end of the 4th, or, maybe, the 6th century of the Christian era.
The great rabbis of the Middle Age are not reckoned as a part of the movement, because their method was far more scientific.
Only a small remnant of the Jews of the captivity returned.
The greater part and the more influential remained in the Persian Empire.
Hence naturally we have Babylonian and Palestinian Rabbinism.
A third element also came into being in the West among the 80 Hellenist Jews who had felt the influence of Greek culture.
Philo was of this contingent.
The great Rabbinical thesaurus and code of laws is the Talmud which divides itself into the Babylonian and Jerusalem Talmuds.
New Catholic Dictionary