Author
- Jean Bayard1
- Jean Filesac1
- Jean Germain1
- Jean Gerson1
- Jean Marot1
- Jean de Malian1
- Johannes Hymmonides1
- Johannes Magistri1
- Johannes de Sacrobosco1
- Johannes von Freiburg1
- John XXII1
- John of Damascus1
- John of Garland1
- John of Saxony1
- Julian of Toledo1
- Julianus Pomerius1
- Kalonymus ben Kalonymus1
- Kimhi Yitzhak ben Mordekhai1
- Kingdom of France1
- Laurent d'Orleans1