The first of its bishops known to history was Sergius (589) and an Archdeacon of Carcassonne, Donnel, is recorded as having subscribed to the acts of the 4th Council of Toledo in 633.

In 1295 Pope Urban addressed a letter to Bishop Pierre, confirming the institution of Clercs Regular of Saint Augustine in the Chapter of the Cathedral.

The Chapter had existed for a considerable time, perhaps going back to Bishop Gimerius in the tenth century, but papal sanction confirmed and strengthened its position as a corporate body living under a Rule.

Notre-Dame-de-Prouille Monastery, where St. Dominic established a religious institute for converted Albigensian women in 1206, is still a place of pilgrimage consecrated to the Blessed Virgin.

From 1848 to 1855 the see was occupied by Bishop de Bonnechose, who was created a Cardinal by Pope Pius IX on 11 December 1863; on 22 September 1864 he was given the red hat and named Cardinal-Priest of San Clemente.