AUCH, ARCHDIOCESE of. — In Gascony, on the left bank of the Gers, A., which today has 133,000 inhabitants, is the metropolitan see of the dioceses of Aire, Bayonne, and Tarbes. Anciently called Elimberrum or Eliberrae (New City), at the time of the conquest of Gaul by Julius Caesar it was the capital of the Auscii, the most important group among the Aquitani. It seems to have received from the Romans the name Augusta, before receiving from the Auscii the definitive name Auscia, Auscius, Civitas Ausciensis, or Auxiensis. When Aquitania was divided, toward the end of the 4th century, A. was one of the twelve civitates of Aquitania III, or Novempopulonia.
The Christian origins of this region remain very obscure. The first bishop of A. known to history is an Oricuzio who lived at the beginning of the 5th century and who appears on 1 May in the Martyrologium Hieronymianum. The diocese of A. then probably comprised the entire Civitas Auscorum, bounded by the archdiocese of Eauze and the dioceses of Toulouse, Tarbes, and Agen. Toward the middle of the 9th century, after Eauze had been destroyed by the Normans, A. inherited, together with the territory of the diocese, the title of metropolitan see, with the suffragan dioceses of Lectoure, Bazas, Aire, Bayonne, Lescar, Oloron, Tarbes, Comminges (St. Bertrand), and Couserans (St. Licerius). It retained these boundaries until the French Revolution. Suppressed in 1801 and united with Agen, the diocese was restored in 1817 and then definitively, on 6 October 1822, by the bull Paternae caritatis. The archbishops, who toward the middle of the 17th century had lost the title of primates of Novempopulonia and the Two Navarrese Kingdoms, resumed the former of these titles in 1829; to it were added those of the suppressed dioceses of Condom, Lectoure, and Lombez.
The archdiocese coincides with the department of Gers. It has 190,000 Catholic inhabitants, 507 parishes, 232 diocesan priests, and 14 religious priests. The major seminary was founded in 1667. Among the shrines, the one of Notre-Dame des Sept-Douleurs at Cahuzac is famous; its origin dates back to 1513, and it has been much frequented by pilgrims ever since. The Revolution of 1789 plundered the chapel, which was restored in 1821; after this it regained its former splendor. It is served by the Assumptionists.