In 650, Saint Nivard, Archbishop of Reims, founded a church in honor of Saint Peter and the Apostles. The Hautvillers site was protected from the barbarian hordes that ravaged the villages of Val-de-Marne at that time. In 658, the villagers of the surroundings came to seek refuge and settled on its heights. During a pilgrimage to Rome in 841, the monk Teutgise stole part of the relics of Saint Helena, mother of Emperor Constantine the Great. He brought them back to the abbey that became a renowned pilgrimage center.