Author
- Isḥāq ibn Ibrāhīm Fārābī1
- Ivo of Chartres1
- Jabir ibn Hayyan1
- Jacob Berab1
- Jacob Israel Karmi1
- Jacob Meyer1
- Jacob ben David ben Yom Tov1
- Jacob ben Machir ibn Tibbon1
- Jacob ben Reuben ibn Zur1
- Jacob ibn Habib1
- Jacobo Bellenden1
- Jacobus Dinetus1
- Jacopo Ragone1
- Jacopone da Todi1
- Jacques Millet1
- Jagannatha Panditaraja1
- Jalal al-Din Davani1
- Jalal al-Din Mohammad Tabrizi1
- Jalāl al-Dīn al-Thīrī1
- James of Viterbo1