Author
- Jacopo Nannis de Piccolomini1
- Jacopo Piccolomini-Ammannati1
- Jacopone da Todi1
- Jalal al-Din al-Suyuti1
- Jean Froissart1
- Jean de Wavrin1
- Jerome1
- Joannes de Crivelli1
- Johannes von Kastl1
- John Cleseby1
- John Gower1
- John Tiptoft, 1st Earl of Worcester1
- John of Glastonbury1
- John of Lancaster, 1st Duke of Bedford1
- John, Duke of Berry1
- Josephus1
- Juana I of Castile1
- Jörg Muelich1
- Khālid ibn ʻAbd Allāh al-Azharī1
- Kingdom of Naples1