- Illegitimacy1
- Illumination of books and manuscripts, Carolingian1
- Illumination of books and manuscripts, Mosan1
- Illumination of books and manuscripts, Renaissance1
- Immortality1
- Immortality--Christianity1
- Indexes1
- India--Goa (State)1
- Indians of Mexico--Legal status, laws, etc.1
- Indians of Mexico--Religion1
- Indians of South America--Legal status, laws, etc.1
- Indians, Treatment of1
- Indulgences (Canon law)1
- Inheritance and succession (Canon law)1
- Inheritance and succession (Roman law)1
- Inner Light1
- Innocent III, Pope, 1160 or 1161-12161
- Innocent IV, Pope, approximately 1200-12541
- Innocent V, Pope, approximately 1224-12761
- Interdict (Canon law)1