Born in Mainz, Germany. An important scholar of his time. As a paytan he composed yozerot, kerovot, selihot, hymns, and rashuyyot le-hatanim. It is probable that he sang his piyutim himself. His piyutim bare traces of the language found in early piyutim, and they are marked by the pain of the persecutions of the Jews in Bar-Isaacs' lifetime.
Sources: Encyclopedia Judaica.