died 1217
Jewish mystic and scholar.
He was a member of the Kalonymos family, which provided medieval Germany with many Jewish mystics and spiritual leaders. Around 1195 he settled in Regensburg, where he founded a yeshiva and gathered disciples such as Eleazar ben Judah of Worms. He was the founder of 12th-century German Hasidism, an ultrapious movement not directly related to 18th-century Hasidism . Book of the Pious , a compilation of the writings of Judah, his father, and Eleazar of Worms, offers a detailed manual of conduct for observant Jews; it is one of the most important documents of medieval Judaism.