Author
- Jacopone da Todi1
- Jacques de Vitry1
- James of Milan1
- Jean de Roquetaillade1
- Jean-François Roussin1
- Jewish Community of Padua, Italy1
- Jewish Community of Pitigliano, Italy1
- Jewish community of unidentified city, Italy1
- Joan Martines1
- Johannes de Sacrobosco1
- John Chrysostom1
- John Wycliffe1
- John XXII1
- John de Breton1
- John de Seccheville1
- Joshua Benzion Segre1
- Leo III1
- Leonardo Mainardi1
- Lope de Olmedo1
- Lorenzo Belo1