- Arte della lana (Guild : Florence, Italy)1
- Artedo, Petrus de1
- Artillery1
- Artisans--Taxation1
- Assumption of the Blessed Virgin Mary1
- Astrology, Iranian1
- Astrology, Roman1
- Astrometeorology1
- Astronomy, Arab1
- Astronomy, Medieval1
- Athīr al-Dīn al-Abharī, al-Mufaḍḍal ibn ʻUmar, -1265. Hidāyat al-ḥikmah1
- Attila, -4531
- Augustinians1
- Augustus, Emperor of Rome, 63 B.C.-14 A.D.1
- Autos-da-fé1
- Badʼ al-amālī (Ūshī, ʻAlī ibn ʻUthmān)1
- Baglioni, Niccolò1
- Bahaüddin Nakşibend, 1318-13891
- Bahjah al-Wardīyah (Ibn al-Wardī, Zayn al-Dīn ʻUmar ibn al-Muẓaffar)1
- Baldini, Antonio1