Author
- Ibn Abi al-Isbaʻ1
- Ibn Daqiq al-Eid1
- Ibn Khalawayh1
- Ibrāhīm ibn Ismāʻīl Ibn al-Ajdābī1
- Ildibrandinus1
- Innocent IV1
- Isidore of Seville1
- Izz al-Din ibn 'Abd al-Salam1
- Jacobus de Voragine1
- Jaghmini1
- Johan de Arcenay1
- Johannes de Sacrobosco1
- John Chrysostom1
- John de Breton1
- John de Seccheville1
- Justinian I1
- Leo Archpriest1
- Muhammad ibn Ja'far al-Khara'iti1
- Muslim ibn al-Ḥajjāj1
- Muḥammad Ibn-Ibrāhīm Ibn-Ǧamāʿa1