Author
- Isaac Israeli ben Joseph1
- Isaak ben Meïr from Düren1
- Isfarāyīnī, Muḥammad ibn Muḥammad, d. 13461
- Ismāʻīl ibn Abī Bakr Ibn al-Muqrī1
- Jacob Anatoli1
- Jacob ben Jacob, ha-Kohen, -approximately 12701
- Jacopo Ragone1
- Jacopone da Todi1
- Jacques Millet1
- Jalal al-Din Davani1
- Jami1
- Jean Dupin1
- Jean de Malian1
- Jean de Meun1
- Jean de Roquetaillade1
- Joannes de Crivelli1
- Joham de Vernoils1
- Johannes Auerbach1
- Johannes Gherinx1
- Johannes Lichtenberger1