- Abbazia di S. Maria di Porcilia (Padua, Italy)1
- Abbeys3
- 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
- Agriculture2
- Alchemy3
- Alexander III, Pope, -11811
- Alexander, the Great, 356 B.C.-323 B.C.4
- Algeria--Hippo (Extinct city)2
- Allegories1
- Alphabet--Religious aspects1
- Alphabet--Religious aspects--Islam1
- Alphabets1
- Ambrosian chants2
- Ambrosian rite (Catholic Church)1
- Andrew, Apostle, Saint1