Author
- Jalaluddin al-Mahalli1
- Jami1
- Jiménez de Enciso, Andrés1
- Joanna I of Naples1
- Joanna of Austria, Princess of Portugal1
- John Frederick II of Saxony1
- John Gage1
- John Skyrrow1
- John de Mowbray, 2nd Baron Mowbray1
- John of Ibelin1
- José Romero de Tejada y Artacho1
- Juan Alvarez1
- Juan Baptista de Gatica1
- Juan Félix de Rújula1
- Juan Ortiz Campoy1
- Juan Perez Barahona1
- Juan de Zumárraga1
- Juana I of Castile1
- Khālid ibn ʻAbd Allāh al-Azharī1
- Kulaynī, Muḥammad ibn Yaʻqūb, -941?1