- Albizzi, Costanza1
- Alchemy--Bibliography1
- Alexander III, Pope, -11811
- Alexander, de Villa Dei. Doctrinale puerorum1
- Alfonso V, King of Aragon, 1396-14581
- Ambassadors1
- Ambrose, Saint, Bishop of Milan, -3971
- Amelius, Martyr1
- Amicus, Martyr1
- Andria (Terence)1
- Angels1
- Annals and chronicles1
- Anne (Mother of the Virgin Mary), Saint1
- Antiphonaries (Service books)1
- Antiphons (Music)1
- Apocryphal and legendary literature1
- Apollonius, of Tyana1
- Apologetic writings1
- Apostles in art1
- Aqueducts1