Author
- 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 Seville ?1
- John of Wales3
- John Dokeianos1
- John, Duke of Berry1
- Jonathan Eybeschutz1
- Jordan von Quedlinburg2
- Josef ibn Tabul2
- Joseph Albaradani1
- Joseph Angelet1
- Joseph Haslewood1
- Joseph Nasi1
- Joseph Trani1
- Joseph Yitzchak Hakohen Poppers1