- Amalarius, Archbishop of Lyon, approximately 775-approximately 8501
- Amboise, Catherine d', 1481?-15501
- Ambrose, Saint, Bishop of Milan, -3973
- Ambrosiaster1
- Anastasius, Sinaita, Saint, active 640-7001
- Andrea da Pistoia1
- Angela, of Foligno, Saint, 1248?-13091
- Angeli, Alessandro degli3
- Antelmi, Bonifazio1
- Antoninus, Saint, Archbishop of Florence, 1389-14594
- Apollonius, of Tyana1
- Arator, Subdiaconus, active 513-5441
- Archiconfraternita dei SS. Ambrogio e Carlo dei Lombardi1
- Ariani, Jacopo (?)1
- Aristotle13
- Aristotle, pseud1
- Arnaldus, Abbot of Bonneval, -approximately 11561
- Artelouche de Alagona1
- Augurelli, Giovanni Aurelio, approximately 1456-1524?1
- Augustine, of Hippo, Saint, 354-43021
