Originally erected in the 5th century, the Diocese of Rodez lost territory when the Diocese of Vabres was created by Pope John XXII on 11 July 1317. In 1801, the diocese was suppressed and its territory split and merged with the Diocese of Cahors and the Diocese of Saint-Flour.
In 1817, the diocese was restored and given jurisdiction over the ancient Diocese of Rodez, with the exception of (1) the deanery of Saint Antonin, which was incorporated with the Diocese of Montauban; (2) the ancient Diocese of Vabres; and (3) a few scattered communes of the Diocese of Cahors.
Modern tradition attributes to St. Martial the foundation of the church of Rodez and the sanctuary of the Blessed Virgin at Ceignac, for according to Cardinal Bourret, the church of Rodez honoured St. Martial as early as the sixth century. There were evidently bishops of Rodez before 475, since Sidonius Apollinaris, in a letter of AD 475, mentions that the Goths left it at that date without bishops.
The Benedictine Abbey of Vabres, founded in 862 by Raymond I, Count of Toulouse. In 1061 or 1062 the abbey was in such a state of decay both in personnel and good order that its abbot, Deusdedit, arranged for it to submit itself to the control of the Abbey of S. Victor in Marseille; the abbot may have been encouraged or ordered by Pope Nicholas II to do so. The abbey and its territory was raised to episcopal rank in 1317, and its diocesan territory was taken from the southeastern portion of the Diocese of Rodez.
The Diocese of Rodez is famous also through the Abbey of Conques and the cult of Saint Faith (Sainte Foy). Some Christians, flying from the Saracens about 730, sought a refuge in the "Val Rocheux" of the Dourdou and built an oratory there. In 790 the hermit Dadon made this his abode and aided by Louis the Pious, then King of Aquitaine, founded an abbey, which Louis named Conques. In 838 Pepin, King of Aquitaine, gave the monastery of Figeac to Conques. Between 877 and 883 the monks carried off the body of the youthful martyr Faith or Foy from the monastery of Sainte Foy to Conques, where it became the object of a great pilgrimage.