Author
- Ibrāhīm ibn Muḥammad ʻIṣām al-Asfarāyīnī1
- Immanuel Bonfils1
- Innocent III1
- Isaac Alfasi1
- Isaac Israeli ben Joseph1
- Isaak ben Meïr from Düren1
- Ismāʻīl ibn Abī Bakr Ibn al-Muqrī1
- Jacobus de Cessolis1
- Jalal al-Din al-Qazwini1
- Jamālī Ardistani1
- Jean Barthélémy1
- Jean Gerson1
- Jean de Wavrin1
- Johann Herolt1
- Johannes Milis1
- John Chrysostom1
- John of Seville ?1
- Jordan von Quedlinburg1
- Juana I of Castile1
- Kamal al-Din ibn al-Humam1