The Longos Vales's Monastery foundation is attributed to D. Afonso Henriques in the second half of the 12th century.
The only enduring element of the primitive medieval construction with its clearly Romanesque style is the main chapel, the remainder of the group was subjected to remodelling work when it passed into the hands of the Society of Jesus.
Nowadays, the monastery is private property, with the exception of the church which continues to be part of the parochial headquarters of the parish.
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).