CARPENTRAS, DIOCESE of. - A small town and ancient diocese in the department of Vaucluse, deriving its name from the Celtic Carpentoracte. The first bishop of whom there is record is Costanzo, who had himself represented at the Council of Riez (439) and was present at those of Orange (441) and Vaison (442). Later there is mention of a Giuliano (517–29), then of Siffredo (Siffrein), who was buried in the basilica of the Holy Trinity at Venasque, which in the 6th century appears to have been united with C., since Clemazio, Siffredo’s successor, at the Council of Orléans in 541 signed as episcopus civitatis Carpentoratensium et Vindascensium.
But until the middle of the 13th century the list of bishops of C. has many gaps. In 1228, by the Treaty of Paris, C., which formed part of the comitatus Vendascensis (whence Comtat venaisin), passed into the possession of the Holy See and became the ordinary residence of the papal legates. In 1475 the diocese, hitherto belonging to the ecclesiastical province of Arles, passed under the jurisdiction of the new diocese of Avignone. From the 16th century many of its bishops were Italians; the diocese was small and in 1709 comprised 29 parishes. Suppressed in 1802, it was definitively incorporated into Avignone in 1818.