Nissim of Gerona

Nissim ben Reuven of Gerona (c. 1315–1376), known by the Hebrew acronym the RaN, was a Catalan rabbi, talmudist and authority on Jewish law, born in Barcelona. He earned his living as a physician.

He served the Barcelona community as judge and teacher and founded a yeshiva there; after criticizing its wealthy leaders he was slandered and imprisoned for five months before being cleared. His pupils included Isaac ben Sheshet and Hasdai Crescas.