Aile - Alme
- Aileran, Saint
- Ailleboust, Family of d'
- Ailly, Pierre d'
- Aimerich, Mateo
- Aire
- Airoli, Giacomo Maria
- Aisle
- Aistulph
- Aix, Archdiocese of
- Aix-en-Provence, Councils of
- Ajaccio, Diocese of
- Akathistos
- Akhmin
- Akominatos, Michael & Nicetas
- al.
- Alabama
- Alabanda
- Alabaster
- Alagoas
- Alagona, Pietro
- Alain Chartier
- Alain de l'Isle
- Alain-Rene Le Sage
- Alalis
- Alaman, Lucas
- Alamanni, Niccolò
- Alan of Tewkesbury
- Alan of Walsingham
- Alanus de Rupe
- Alanus de Rupe (Alanus de la Roche)
- Alarcón, Pedro Antonio de
- Alaska
- Alatri
- Alb
- Alb.
- Alba Pompeia, Diocese of
- Alban Butler
- Alban Isidor Stolz
- Alban, Saint
- Albanenses