Author
- John Shirley1
- John Tiptoft, 1st Earl of Worcester1
- John Versor1
- John Wycliffe1
- John XXI1
- John Zonaras1
- John of Damascus1
- John of Garland1
- John of Glastonbury1
- John of Howden1
- John of Lancaster, 1st Duke of Bedford1
- John of Seville ?1
- John, Duke of Berry1
- Joseph Angelet1
- Joseph Haslewood1
- Joseph ben Abraham Gikatilla1
- Joseph ben Moses Sarfati1
- Juan de Torquemada1
- Juana I of Castile1
- Judah ben Saul ibn Tibbon1