San Gianuario is a Roman Catholic church in Marsico Nuovo, Basilicata. It is cited as the co-cathedral of the town along with the church of San Giorgio.
The church is thought to have been erected at the site of a pagan Serapeum, and that some of the capitals of the columns are spolia from such a temple. The site had a pre-Christian cemetery. Documents maintain the Abbey of Santo Stefano was erected here under the patronage of a Count Osmondo during the rule of the Norman Robert Guiscard in the region. The abbey putatively held the relics of San Gianuario, a 4th-century bishop martyred nearby by Diocletian. The abbey however fell into disuse and ruin, leaving behind only this church. The structure has been refurbished over the centuries.
The church houses a number of artworks including a detached fresco derived from the church of San Francesco. The church has paintings by Simonelli, Feliciano Mangieri and Nicola Peccheneda. A stone portal, attributed to Melchiorre da Montalbano, consists of flanking column-pilasters with bas-reliefs of bishops. In a niche above the portal is a half-figure bust of San Stefano. The bronze doors (1699) are by Antonio Masini.
References:Saint-Georges de Boscherville Abbey is a former Benedictine abbey. It was founded in about 1113 by Guillaume de Tancarville on the site of an earlier establishment of secular canons and settled by monks from the Abbey of Saint-Evroul. The abbey church made of Caumont stone was erected from 1113 to 1140. The Norman builders aimed to have very well-lit naves and they did this by means of tall, large windows, initially made possible by a wooden ceiling, which prevented uplift, although this was replaced by a Gothic vault in the 13th century. The chapter room was built after the abbey church and dates from the last quarter of the 12th century.
The arrival of the Maurist monks in 1659, after the disasters of the Wars of Religion, helped to get the abbey back on a firmer spiritual, architectural and economic footing. They erected a large monastic building one wing of which fitted tightly around the chapter house (which was otherwise left as it was).