Author
- John Burgh1
- John Capgrave1
- John Chrysostom1
- John Gower1
- John Mandeville1
- John XXII1
- John of Genoa1
- John of Seville ?1
- John, Duke of Berry1
- Jordan von Quedlinburg1
- Joseph Angelet1
- Joseph ben Abraham Gikatilla1
- Juana I of Castile1
- Judah ben Saul ibn Tibbon1
- Junayd ibn Sandal Baghdādī1
- Kamal Khujandi1
- Kamal al-Din ibn al-Humam1
- Khayr al-Dīn Khalīl1
- Khvājah Muḥammad Pārsā1
- Kingdom of Naples1