Author
- John de Mowbray, 2nd Baron Mowbray1
- John de Seccheville1
- John of Damascus2
- John of Garland2
- John of Genoa2
- John of Glastonbury1
- John of Howden1
- John of Ibelin1
- John of Lancaster, 1st Duke of Bedford1
- John of Saxony1
- John of Seville1
- John of Wales3
- John Dokeianos1
- John, Duke of Berry1
- Jonas King1
- Jonathan Eybeschutz1
- Jordan von Quedlinburg2
- Josef ibn Tabul2
- Joseph Albaradani1
- Joseph Angelet1