(Ran) Rabbeinu Nissim of Gerona

Rabbi Nissim ben Reuven of Girona (the Ran) was the leading Talmudist of Barcelona in the mid-1300s, and he also practiced as a physician. His commentary on the Rif's Halakhot, Rabbi Isaac Alfasi's digest of the Talmud, became a standard companion to it. His commentary on tractate Nedarim is so central that the standard Vilna Talmud prints it on the page in place of Rashi's. He also left novellae on many tractates and about 77 responsa.

His Derashot HaRan, twelve philosophical sermons, discuss prophecy, miracles and the relationship between the Sanhedrin and the king. They remain one of the classic works of medieval Jewish political thought. His students included Rabbi Yitzhak ben Sheshet (the Rivash) and the philosopher Hasdai Crescas. Through them his method passed to the generation that saw the catastrophe of 1391.