Abbey of Saint-Germain-des-Prés
He was chosen as building contractor for Mont Saint-Michel in the 11th century. He designed the Romanesque church of the abbey, daringly placing the transept crossing at the top of the mount. Many underground crypts and chapels had to be built to compensate for this weight. These formed the basis for the supportive upward structure that can be seen today. He also rebuilt the Abbey of Saint-Germain-des-Prés.