Author
- Jacopo Ragone1
- Jaghmini1
- Jakob Christoph Blarer von Wartensee1
- Jalal al-Din al-Suyuti1
- Jean Manesca1
- Joannes Dominicus de Marchis1
- Joham de Vernoils1
- Johannes Mellarinus1
- Johannes Tostius1
- Johannes von Kastl1
- John Cornelius1
- John Frederick II of Saxony1
- John of Ibelin1
- Juan de Torquemada1
- Kamal al-Din ibn al-Humam1
- Kamāl al-Dīn Turkumānī1
- Khālid ibn ʻAbd Allāh al-Azharī1
- Kingdom of Bohemia1
- Konrad III. von Soltau1
- Kurdī Sayyidī Maḥmūd ʻAjamī1