- Italy--Padua1
- Italy--Pinerolo1
- Italy--Verona1
- Italy--Villanova Monteleone1
- Izmīrī, Muṣṭafá ibn Rajab, active 17th century1
- Iṣfahānī, Maḥmūd ibn ʻAbd al-Raḥmān, 1275 or 1276-1348 or 1349. Tasdīd al-ʻaqāʾid fī sharḥ Tajrīd al-qawāʻid1
- Japan1
- Japanese poetry1
- Jaʻbarī, Arslān ibn Yaʻqūb, -1300. Risālat al-tawḥīd1
- Jesuit drama, Spanish1
- Jewish astronomy1
- Jewish courts1
- Jewish interpretations of Jesus Christ1
- Jewish magic1
- Jewish religious poetry, Judeo-Arabic1
- Jews--Medicine1
- Jews--Persecutions1
- John I, King of Portugal, 1357-14331
- Joseph Della Reina, active 15th century1
- Juana, of Austria, Princess of Portugal, 1535-15731