Many consider that the prieural chapel and the parish church formed only one building, the whole called «the chapel of Saint-Arnoult».
Their function and vocation were not the same.
The priory chapel founded in 1061 depended on the monastery of Longpont-sur-Orge (91). Our Priory is distinguished by not being a Norman foundation and being a Cluniac Benedictine with a titular Prior.
It is the first Cluniac foundation in Normandy!
Moreover, architecturally, it is reminiscent of the Romanesque architecture of Mt. St. Michel: indeed, there are two levels: a crypt (or low oratory) and the chapel (or high oratory). The parish church was run by a parish priest.
The two buildings, the chapel and the church, therefore had a distinct holder.
Although partially in ruins, the church still offers a romantic charm underlined by two architectural eras: Romanesque and Gothic. St. Clair, priest and martyr, "witness", was born in 845 in Kent, England. His father, "Great Lord", commendable in his worth and piety, held the second rank at court after the King. Like Anne, her barren mother, offered fervent prayers to God with her husband to obtain a child. Their vows were granted and God gave them a son... He was so beautiful, so pleasant, and so well-made that at his baptism he received the name of Clair. In our Cotentin, Clair embraced religious life. He performed miracles there, out of charity, wishing, in vain, always the greatest discretion.
Since then, Saint Clair is invoked, in Saint Clair sur Epte and throughout Normandy, for the affections of sight and headaches.
St. Arnoul was born around 480 in Reims. His parents, pagans of high lineage, seemed barren until they converted and received the baptism of Saint Rémi, bishop of Reims, before that of Clovis. Arnoul, the much desired child, came into the world and was consecrated to God. He became an adviser to the young Clovis coming to power.
A few months later, he was brutally assaulted in a street of Reims by his wife’s clan. Arnoul having wished, in his last breath, that his remains rest, like all the bishops of Tours, at the tomb of Saint Martin. For mysterious reasons, the convoy never reached its destination. This place, exactly halfway between Reims and Tours, became the burial place of Arnoul and this place took its name: Saint Arnoul en Yvelines.
Saint Arnoul is considered the patron saint of walkers and also protector of small children.