Isaac ben Jacob Alfasi (1013–1103) (, ) - also known as the Alfasi or by his Hebrew acronym Rif (Rabbi Isaac al-Fasi), was a Maghrebi Talmudist and posek (decider in matters of halakha - Jewish law). He is best known for his work of halakha, the legal code Sefer Ha-halachot, considered the first fundamental work in halakhic literature. His name "Alfasi" means "of Fez" in Arabic, but opinions differ as to whether he ever lived in Fez. Biography He was born in Qalaat Hammad, which is understood by most historians of the past 100 years to be Qalaat Beni Hammad in modern-day Algeria, capital city of the Hammadid rulers of central Maghreb. However, older sources believe Qalaat Hammad refers to a village near Fez. In the former case, Alfasi's name would indicate that his family had ancestry in Fez, an idea which is supported by the frequent reference to him as "ben Alfasi" or "ibn Alfasi" by the authorities closest to him in time and place. He studied in Kairouan, Tunisia under Rabbeinu Nissim ben Jacob, and Rabbeinu Chananel ben Chushiel the recognized rabbinical authorities of the age. Rabbeinu Chananel trained Alfasi to deduce and to clarify the Halakha from Talmudic sources, and Alfasi then conceived of the idea of compiling a comprehensive work that would present all of the practical conclusions of the Gemara in a clear, definitive manner. To achieve this goal, he worked for ten consecutive years in his father-in-law's attic. In 1045, Alfasi moved to Fez with his wife and two children. (However, Binyamin Ze'ev Benedict and other recent scholars argue that Alfasi was never active in Fez.) Fez's Jewish community undertook to support him and his family so that he could work on his Sefer Ha-halachot undisturbed. They also founded a yeshiva in his honor, and many students throughout Morocco came to study under his guidance. The most famous of his many students is Rabbi Judah Halevi, author of the Kuzari; he also taught Rabbi Joseph ibn Migash (the Ri Migash), who was in turn a teacher of Rabbi Maimon, father and teacher of Maimonides (Rambam). Alfasi remained in Fez for 40 years, during which time he completed his Sefer Ha-halachot. In 1088, aged seventy-five, two informers denounced him to the government upon some unknown charge. He left Fes for Al-Andalus, eventually becoming head of the yeshiva in Lucena in 1089. His "magnanimous character" is