The Cathedral of Our Lady of Nazareth, the mother church of the diocese of Vaison (about forty parishes in the Papal State and the Dauphiné), was in the centre of a medieval city that has since disappeared. The bishop resided in the nearby episcopal palace and the canons in the cloister and its adjoining buildings. Built in the eleventh century on the site of Paleo-Christian buildings, according to a basilical plan, then redesigned in the following century, its architecture is a very good example of Provençal Romanesque art. One of its characteristics is the presence of ancient vestiges reused during its construction. Adjacent to the cathedral, the cloister has four galleries surrounding the garden, with small arcades grouped by three under discharge arches. The columns are topped with water-leaf capitals for the most part, but some are figurative. The rooms reserved for canons (refectory, dormitory, chapter hall, etc.), served by the cloister gallery, have now disappeared. The cathedral thus transformed consists of a central nave of three bays, flanked by two collaterals without transept. The tripartite chevet includes a rectangular central apse on the outside and semi-circular on the inside. The nave is vaulted in broken barrel on double. The collateral have creeping vaults. The shady surroundings and the tranquility of the cloister make it a pleasant place to visit.