RIEZ. - An ancient diocese in the department of the Basses-Alpes, in France. A Ligurian city, it was later the capital of the Reii, whence the name *Regium*, from which the present name derives. It was a colony with Latin rights under Augustus. The first known bishop is Prosperus, predecessor of St MAXIMUS (434-60); he was succeeded by Faustus (462-95), formerly abbot of Lérins.
Riez was sacked by the Saxons in 572; the inhabitants and the bishop abandoned the city, which suffered further in the Saracen raids from 793 to 875. Bishop Edolus later transferred the see to the hill in the chapel of St MAXIMUS, where the inhabitants also moved. Among its prelates are remembered Cardinals Pierre Després in 1318 and Guido Bentivoglio. The diocese, a suffragan of Aix, was suppressed in 1790; in 1801 its territory was united to the see of Digne, whose bishop since 1916 also bears the title of Riez. Bishop Augerius (1096-1130) rebuilt the cathedral and the baptistery; the former, Notre-Dame-de-la-Sède, fell into ruin in the 15th century; near the present church some Gothic bays remain. The baptistery was of Provençal and Ligurian type, a four-sided building externally, surmounted by an octagonal tower which was damaged during the Saracen raids. The interior is an octagon of m. 9.25 x 8.40 with four apses and a circular ambulatory; eight Roman columns of Var granite support the dome. The floor has been raised subsequently and the bases of the columns are partly cut off. The baptistery was abandoned at the end of the 16th century and the inhabitants called it the Pantheon; ceded to the Confraternity of Tailors, it was consecrated to their patron St CLAIR; then it passed to the White Penitents; at present it is reduced to an archaeological museum. On the Hill of St MAXIMUS the chapel, rebuilt in 1857, preserves a Roman apse with an ambulatory supported by six Corinthian columns. From the papers of Peiresc it appears that in the floor mosaic of the cathedral of Riez was the image of Constantine on horseback trampling a vanquished foe; the scene was accompanied by the couplet:
*Rex Constantinus, leprosus, virque benignus,*
*est factus sanus sacro baptismate tactus.*
This recalled the legend of the Emperor cleansed of leprosy through baptism (R. Mowat, *Mosaïque de R. offrant l'image de Constantin*, in *Bull. de la Soc. des antiquaires de France*, 1885, pp. 68-71).