- Alexander, the Great, 356 B.C.-323 B.C.1
- Ambrosian chants1
- Ambrosian rite (Catholic Church)1
- Anselm, Saint, Archbishop of Canterbury, 1033-11091
- Antiphons (Music)1
- Apocryphal Gospels1
- Apocryphal books (New Testament)1
- Apologetic writings1
- Apologetics1
- Arabic language--Foreign words and phrases1
- Aristotle1
- Art1
- Asceticism1
- Asceticism--Early church1
- Astrolabes1
- Astronomy in rabbinical literature1
- Authors, Latin1
- Avodah (Yom Kippur liturgy)1
- Bede, the Venerable, Saint, 673-7351
- Ben Yijû, Abraham, active 12th century1