Rabbeinu Gershom

Rabbeinu Gershom heads the academy at Mainz and is remembered as Me'or HaGolah, the Light of the Exile, for establishing Ashkenazi Jewry as a center of learning independent of Babylonia. He issues a series of binding ordinances, most famously the ban on polygamy and the prohibition against divorcing a woman against her will. He also rules that letters may not be opened by anyone other than their recipient, an early principle of privacy. His decrees still govern Ashkenazi practice a thousand years later, and his students train the generation that produces Rashi.