Author
- John Larry England1
- John Lydgate1
- John Mandeville1
- John Tiptoft, 1st Earl of Worcester1
- Jordan von Quedlinburg1
- Joseph Haslewood1
- João Freire1
- Juan Gallo1
- Juan Martínez Silíceo1
- Juan Ortiz Campoy1
- Juan de Zumárraga1
- Kamal al-Din ibn al-Humam1
- Kamāl al-Dīn Turkumānī1
- Khaqani1
- Kingdom of England1
- Kingdom of France1
- Klaus von Stille1
- Leo I1
- Leon Battista Alberti1
- Lorenzo Valla1