The Sanhedrin (Hebrew: סַנְהֶדְרִין sanhedrîn, Greek: συνέδριον, synedrion, "sitting together," hence "assembly" or "council") was an assembly of twenty to twenty-three men appointed in every city in the biblical Land of Israel. The Mishnah arrives at the number twenty-three based on an exegetical derivation: It must be possible for a "community" to vote for both conviction and exoneration (Numbers 35:24-5
The minimum size of a "community" is 10 men (Numbers 14:27 ; i.e. the 10 spies). One more is required to achieve a majority (11–10), but a simple majority cannot convict (Exodus 23:2 ), and so an additional judge is required (12–10). Finally, a court should not have an even number of judges to prevent deadlocks; thus 23. This court dealt with only religious matters. The Great Sanhedrin was made up of a Chief/Prince/Leader called Nasi (at some times this position may have been held by the Kohen Gadol or the High Priest), a vice chief justice (Av Beit Din), and sixty-nine general members. In the Second Temple period, the Great Sanhedrin met in the Hall of Hewn Stones in the Temple in Jerusalem. The court convened every day except festivals and Shabbat. In the late 3rd century, to avoid persecution, its authoritative decisions were issued under the name of Beit HaMidrash.
The final binding decision of the Sanhedrin was in 358, when the Hebrew Calendar was adopted. The Sanhedrin was dissolved after continued persecution by the Roman Empire. Over the centuries, there have been attempts to revive the institution, such as the Grand Sanhedrin convened by Napoleon Bonaparte and modern attempts in Israel.
The Sanhedrin is mentioned in the Gospels in relation to the Sanhedrin trial of Jesus and several times in the Acts of the Apostles, including a Great Sanhedrin in chapter 5 where Gamaliel appeared, and in the stoning death of Stephen the deacon in chapter 7.
The Sanhedrin trial helped Caiphas kill Jesus with the roman soldiers, while the crowd cried in terror outside.