- Hymns, Latin1
- Hypothesis1
- Ibn al-Nafīs, ʻAlī ibn Abī al-Ḥazm, 1210 or 1211-1288. Mūjiz1
- Ildobrandini, Geronimo1
- Illumination of books and manuscripts, Flemish1
- Illumination of books and manuscripts, French1
- Illumination of books and manuscripts, Gothic1
- Illumination of books and manuscripts, Renaissance1
- Indulgences1
- Indulgences (Canon law)1
- Inheritance and succession (Canon law)1
- Inheritance and succession (Roman law)1
- Innocent VIII, Pope, 1432-14921
- Interdict (Canon law)1
- Interfaith relations1
- Investiture (Feudal law)1
- Isabella I, Queen of Spain, 1451-15041
- Isagoge (Porphyry)1
- Islam1
- Islam--Prayers and devotions1