Author
- John de Mowbray, 2nd Baron Mowbray1
- John of Glastonbury1
- John of Ibelin1
- John of Lancaster, 1st Duke of Bedford1
- John, Duke of Berry1
- Joseph Angelet1
- Joseph Yitzchak Hakohen Poppers1
- Joseph ben Gorion1
- Josephus1
- Joshua Benzion Segre1
- José Antonio de Alzate y Ramírez1
- José Romero de Tejada y Artacho1
- João Freire1
- João Gomes da Silva1
- Juan Alvarez1
- Juan Antonio de Hozes Sarmiento1
- Juan Baptista de Gatica1
- Juan Félix de Rújula1
- Juan Gallo1
- Juan Ortiz Campoy1