Author
- Iacopo da Benevento1
- Ildibrandinus1
- Imbert Feutrier1
- Innocent III1
- Innocent IV1
- Isaac Israeli ben Solomon1
- Isidore of Seville1
- Ivo of Chartres1
- Jacobus Balbi1
- Jacobus Dinetus1
- Jacobus de Burgo1
- Jacobus de Voragine1
- Jacomo Veronese1
- Jacopo Nannis de Piccolomini1
- Jacopo Ragone1
- James of Lausanne1
- Jean Carteron1
- Jean Passerat1
- Jerome1
- Joanna I of Naples1