- Abbazia di S. Maria di Porcilia (Padua, Italy)1
- Abū al-Layth al-Samarqandī, Naṣr ibn Muḥammad, -983? Muqaddimah1
- Accademia degli Humoristi (Rome, Italy)1
- Accounting--Handbooks, manuals, etc.1
- Aeneas (Legendary character)1
- Agamemnon, King of Mycenae (Mythological character)1
- Aggada1
- Alexander III, Pope, -11811
- Allegories1
- Alphabet--Religious aspects1
- Alphabet--Religious aspects--Islam1
- Alphabets1
- Ambrosian rite (Catholic Church)1
- Andrew, Apostle, Saint1
- Anecdotes1
- Angulo family1
- Angulo, Alonso de1
- Anselm, Saint, Archbishop of Canterbury, 1033-11091
- Anthony, of Padua, Saint, 1195-12311
- Anti-Catholicism1