- Ibn al-Nāẓim, Muḥammad ibn Muḥammad, d. 1287 or 8. Sharḥ al-Alfīyah1
- Ibn al-Sāʻātī, Aḥmad ibn ʻAlī, 1254-1294 or 1295. Badīʻ al-niẓām al-jāmiʻ bayna Kitāb al-Bazdawī wa-al-aḥkām1
- Ibn ʻAqīl, ʻAbd Allāh ibn ʻAbd al-Raḥmān, 1294?-1367. Sharḥ al-Alfīyah1
- Illegible markings1
- Illumination of books and manuscripts, Renaissance1
- Immortality1
- Indexes1
- Indulgences1
- Indulgences (Canon law)1
- Inheritance and succession (Canon law)1
- Inheritance and succession (Roman law)1
- Initials (Abbreviations)1
- Innocent III, Pope, 1160 or 1161-12161
- Inquisition1
- Intellectual life1
- Interdict (Canon law)1
- International trade1
- Iran--Zarqān (Fārs)1
- Ireland1
- Isabel, of Coimbra, Queen, consort of Afonso V, King of Portugal, 1432-14551