Eliezer ben Joel HaLevi

Eliezer ben Yoel HaLevi of Bonn (Hebrew acronym Rav'Yah; 1140–1225 ) was a Rabbinic scholar in Germany. He is perhaps best remembered for reintroducing the principle of majority decision making (elsewhere known as Democracy) into the procedure of Rabbinic courts. Eliezer of Bonn's defense of the principle of majority rule shows up in the writings of Meir of Rothenburg,

Meir of Rothenburg's epitome of Eliezer's defense of the principle of majority rule on questions of community legal practices, indicate that this principle was reintroduced at the Takkanot SHUM: The Jewish synods held at Speyer, Worms and Mainz in the midst of their persecution during the Crusades. There Eliezer of Bonn presided alongside his friend and companion Eleazar of Worms, a mystical teacher from the Kalonymid Dynasty, and other members of the Jewish community in Western Europe.

His major work, Sefer Avi HaEzri (My Father is my Help), which is more commonly known by its author's acronym as Sefer Ra'avyah (also spelled Sefer Rabiah), is a compendium of articles that he developed into a book. It contains halakhot and legal decisions.