Author
- Julianus Pomerius1
- Jullien Gervais1
- Junayd ibn Sandal Baghdādī1
- Justin1
- Justinian I1
- Jörg Muelich1
- Kalonymus ben Kalonymus1
- Kamal Khujandi1
- 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
- Kingdom of Naples1
- Klaus von Stille1
- Konrad III. von Soltau1
- Lambert le Bègue1
- Laurentius Cynthius1
- Leo Archpriest1
- Leonardo Mainardi1