A German rabbi, who died as a martyr at Nuremberg in 1298. His great legal (Halachic) work is usually cited as "the Mordecai," and its value consists in its thorough use of the medieval authorities. It acquired wide authority, and was one of the sources of the Code of Joseph Caro. Mordecai was also the author of Responsa. See L. Ginzberg in Jew. Ency. ix. 10-13.