Complex sentence: For the Jews of late antiquity and the early Middle Ages, the yeshivot of Babylonia served much the same function as the ancient Sanhedrin, i.e., as a council of Jewish religious authorities.
Split into simpler sentences: For the Jews of late antiquity and the early Middle Ages, the yeshivot of Babylonia served much the same function as the ancient Sanhedrin. That is, as a council of Jewish religious authorities.