Av Beit Din

The av beit din (Hebrew: אָב בֵּית דִּין, romanized: ʾāḇ bēṯ din, lit. 'chief of the court, chief justice'), abbreviated abd (אב״ד avad), was the second-highest-ranking member of the Sanhedrin during the Second Temple period and served as an assistant to the nasi. The av beit din was known as the "Master of the Court;" he was considered the most learned and important of these seventy members. Menahem the Essene served as av beit din in the 1st century BC before abdicating to "serve the King" in 20 BC. The House of Shammai attained complete ascendency over the Sanhedrin from 9 CE until Gamaliel became nasi in 30 CE. The post of av beit din was eventually filled since the Babylonian Talmud states that Joshua ben Hananiah was the av beit din in Baba Kamma 74b and Nathan the Babylonian was av ...