Author
- John XXI1
- John of Glastonbury1
- Jordan von Quedlinburg1
- Joseph Angelet1
- Joseph ben Abraham Gikatilla1
- Joseph ben Moses Sarfati1
- Josephus1
- Juan de Torquemada1
- Judah ben Saul ibn Tibbon1
- Jullien Gervais1
- Junayd ibn Sandal Baghdādī1
- Jörg Muelich1
- Kalonymus ben Kalonymus1
- Kamal al-Din ibn al-Humam1
- Khayr al-Dīn Khalīl1
- Khaṭīb Qādā, ʻAbd Allāh ibn Muḥammad, active 15th century1
- Khvājah Muḥammad Pārsā1
- Khālid ibn ʻAbd Allāh al-Azharī1
- Kingdom of England1
- Konrad III. von Soltau1