- Astrology and death1
- Astronomy7
- Astronomy, Arab1
- Astronomy, Medieval2
- Astronomy--Popular works1
- Aubertus, de Galardone1
- Augustine, of Hippo, Saint, 354-4303
- Augustinians4
- Austria1
- Badʼ al-amālī (Ūshī, ʻAlī ibn ʻUthmān)1
- Barbarossa, -15461
- Barrois, Joseph, approximately 1785-18551
- Barsauma, -4581
- Bartholomeo, de Soncino1
- Bartholomew, of San Concordio, 1262-13471
- Basilica di San Marco (Venice, Italy)1
- Bassianus, of Glisate1
- Bateman family1
- Battiferri degli Ammannati, Laura, 1523-15891
- Battle of Lepanto (Greece : 1571)2