Author
- Immanuel Bonfils1
- Innocent VIII1
- Innocent XI1
- Isaac Alfasi1
- Isaac Israeli ben Joseph1
- Isaak ben Meïr from Düren1
- Isidore of Seville1
- Ismāʻīl ibn Abī Bakr Ibn al-Muqrī1
- Jacobus de Cessolis1
- Jacobus de Teramo1
- Jacopo Ragone1
- Jacopone da Todi1
- Jacques Legrand1
- Jacques Millet1
- Jaghmini1
- Jakob Wimpfeling1
- Jalal al-Din Davani1
- Jalal al-Din al-Qazwini1
- James of Lausanne1
- James of Milan1