Author
- Isaac Israeli ben Joseph1
- Isaak ben Meïr from Düren1
- Isfarāyīnī, Muḥammad ibn Muḥammad, d. 13461
- Jacob Anatoli1
- Jacomo Veronese1
- Jacopone da Todi1
- Jacques Millet1
- Jakob Wimpfeling1
- Jalal al-Din al-Suyuti1
- Jalaluddin al-Mahalli1
- James of Lausanne1
- Jean Dupin1
- Jean Froissart1
- Jean Le Fèvre de Ressons1
- Jean de Roquetaillade1
- Jean de Wavrin1
- Joannes de Crivelli1
- Johann Reger1
- Johannes Gherinx1
- Johannes Lichtenberger1