[m., pl. "Sanhedriyaot"] – 1. the Jewish “Supreme Court;” it consisted of seventy one great Torah Sages, who met in the “Lishkat HaGazit,” the “Office of Hewn Stone,” adjacent to the Temple in Jerusalem; 2. The Masechta, or Folio of the Talmud that discusses the activities of the Sanhedrin, and related matters.
The Rabbis who were the members of the Sanhedrin had all received “Semichah,” the formal passing over of the Tradition from their teachers.
On the floor of the Sanhedrin were debated the fundamental principles of the Torah, and the result was established by majority vote.
Cases that were the most difficult or the most critical for the Jewish People were decided by the Sanhedrin. A majority had to be at least two votes. Any Capital case in which all the votes were for condemnation, was automatically changed to acquittal.
There is discussion in the Talmud of the question of how frequently capital punishment was imposed by the Sanhedrin, although the Torah does explicitly allow for it. Some said that a Sanhedrin that imposed the death penalty once in seven years was considered “bloody;” another opinion is that it was seventy years. Another said that it depended on the generation. Yet another was that restraint in imposing the death penalty would increase the number of murderers in Israel.
After the Temple was destroyed, the Sanhedrin moved from place to place in Israel. It finally was dissolved when, in the absence of the greatest Sages of Israel, the Institution of Semichah could no longer be applied.
During the Middle Ages, there was an attempt to revive the Sanhedrin by re-instituting Semichah. But due to opposition by some of the Torah Sages of that generation, the idea never became a reality.