The Cattolica was built in the 9th century, when Calabria was part of the Byzantine Empire. The name derives from the Greek word katholiki, which referred to the churches provided with a baptistery. It is one of the most important examples of Byzantine architecture, together with the church of San Marco in Rossano Calabro.
The Cattolica follow a plan with 'inscribed cross', typical of the middle Byzantine age. The interior is divided by four columns into five similar spaces. The square central space and the angled ones are covered by domes. The angled ones have tambours with the same diameter, while the central dome is slightly taller and larger.
The western sides lies on free rocks, while the southern area, ending with three apses, stands on three stone bases. The construction is in bricks.
The interior was once entirely covered with frescoes. The left apse has a bell built in 1577, when the church was converted to the Latin rite. The interior has also several inscriptions in Arabic, which have led scholars to suspect it could have been also used as a Muslim oratory.
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).