AQUENSIS (Dax - Landes)Probably third century, reduced several times to the benefit of Labourd, Bayonne and Oloron (between the eighth and the eleventh century). Incorporated in the tenth century with its neighbouring dioceses, in the short-lived diocese of Gascogne.
ARELATENSIS (Arles - Bouches-du-Rhônes)Known from the middle of the second century.
ARGENTINENSIS (Strasbourg - Bas-Rhin)Created in the first half of the fourth century.
ARISITENSIS (Le Vigan - Gard)Created in the sixth century, but absorbed by the See of Nîmes in the seventh century.
ATREBATENSIS (Arras - Pas-de-Calais)Created about 500. Transferred to Cambrai about 540, and reestablished at Arras in 1093.
AURASICENSIS (Orange - Vaucluse)Created at the beginning of the fourth century.
AURELIANENSIS (Orléans - Loiret)Mentioned in at the beginning of the fourth century.
AUTISSIODORENSIS (Auxerre - Yonne)Founded in the second century.
AUXITANENSIS (Auch - Gers)Mentioned in the fourth century. Merged in the ninth century with Eauze. Archbishopric in the ninth century.
AVINIONENSIS (Avignon - Vaucluse)Created without doubt in the fourth century, and seat of the Popes between 1309 et 1377, then a simple possession of the Holy See until the French revolution. Seat of and archbishop since 1475.