Founded in 804 by Benedictine Monks, ordered by count Eribert, the abbey was raised on a desert and inhospitable place. Bishops of Arles protected it, and kings and princes embellished it. Even a church was added in 970! In the 11th century, monks built new buildings on a rock: oh, they just wanted to protect themselves from river Rhône's floods... And what floods! One of them at the end of the 12th century overran the church and let a 4 metres thick gravel bed! Monks were forced to raise the soil inside and outside.
During the war of Religion, Cruas, a Catholic place, was besieged by Protestants: but our monks, led by abbot Etienne Déodel, bishop of Grasse, threw them out after they murdered masses of them! The church had 2 crypts: one from the 11th century, the other from the 13th century. The "upper church" was raised at the end of the 11th century.