- Apocryphal and legendary literature1
- Apollonius, of Tyana1
- Apparitions1
- Aqueducts1
- Aramaic language1
- Architecture--Orders1
- Arithmetic--Study and teaching1
- Armies1
- Arnaldus, de Villanova, -13111
- Arrighi family1
- Ashkenazim1
- Assassination1
- Astronomy, Greek1
- Aurispa, Giovanni, approximately 1376-14591
- Avodah (Yom Kippur liturgy)1
- Bankers1
- Bardi, Giovanni de', conte di Vernio, 1534-16121
- Bartolomeo, da Petroio, 1488?-15541
- Basil, Saint, Bishop of Caesarea, approximately 329-3791
- Basilica di S. Marco Evangelista al Campidoglio (Rome, Italy)1