Author
- Jacobus de Cessolis1
- Jalal Al-Din Al-Khabazi1
- Jalal al-Din al-Qazwini1
- Jalaluddin al-Mahalli1
- Jamāl al-Dīn Aḥmad ibn Muḥammad Ẓāhirī1
- Jamāl al-Dīn Ḥaṣīrī1
- Jean Dupin1
- Jean de Lignieres1
- John Cassian1
- John Gower1
- John Larry England1
- John XXII1
- Joseph ben Abraham Gikatilla1
- Joseph ben Judah ibn Aknin1
- Kalāʼī, Muḥammad ibn Sharaf, d. 13751
- Mahmud ibn Ali al-Qashani1
- Majd ad-Dīn Ibn Athir1
- Malik ibn Anas1
- Martin of Opava1
- Matthew of Vendôme1