Author
- Johannis Hieronymus1
- John Capgrave1
- John Cassian1
- John Dominici1
- John Halgren of Abbeville1
- John Shirley1
- John Tiptoft, 1st Earl of Worcester1
- John Versor1
- John Wycliffe1
- John XXI1
- John Zonaras1
- John of Garland1
- John of Howden1
- John of Seville ?1
- Joseph Haslewood1
- Joseph ben Moses Sarfati1
- Judah ben Saul ibn Tibbon1
- Julianus Pomerius1
- Jullien Gervais1
- Junayd ibn Sandal Baghdādī1