The Co-Cathedral of the Assumption of Mary was built in 1169 as a Romanesque basilica of a single nave on the foundations of a pagan temple of the fourth and fifth centuries, whose remains are still visible at the back of the sanctuary at about 1.5 meters deep. The façade and the south side of the cathedral, in the middle of the eighteenth century was decorated with Romanesque arches and brick niches. In the same period the church was expanded with the addition of two side aisles, altars and other works of art. During World War II the cathedral was severely damaged. The current appearance of the building is the result of the restoration executed between 1949 and 1950.
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).