Author
- Isaac Alfasi1
- Isaac Israeli ben Joseph1
- Israel Sarug1
- Jabir ibn Hayyan1
- Jacob Israel Karmi1
- Jacob Saphir1
- Jacob ben David ben Yom Tov1
- Jacobus de Cessolis1
- Jacopone da Todi1
- Jacques de Vitry1
- James of Viterbo1
- Jean de Roquetaillade1
- Jewish Community of Pitigliano, Italy1
- Jewish community of unidentified city, Italy1
- Joannes de Crivelli1
- John Dominici1
- John XXI1
- John XXII1
- John de Breton1
- John de Seccheville1