The earliest part of the present church dates from the beginning of the 11th century, the choir and apse from the second half of the 12th century. The best view of the apse with its flying-buttresses is to be obtained from the garden of the abbot's palace; but since the clearing away of the houses which formerly were almost built on to the church, and the planting of gardens round it, the view is very picturesque from any point. An insignificant 17th century porch leads to the west door, which is underneath the tower, and has, in its tympanum, a much mutilated bas-relief of _The Last Supper_. The tower has been so much restored and renovated from time to time that little of the original remains. It has a high, but stumpy spire covered with slates. Dom Bouillart relates that on the 2nd November, 1589, Henri IV. mounted to the top of it (accompanied by only one ecclesiastic) to examine the situation of Paris; and, continued the monk, "He afterwards walked round the cloisters, and without speaking one word, departed." Of the other two towers which were formerly at the angles of the choir and transepts, nothing remains but the bases, which were considered necessary for the support of the church. It seems that they were pulled down about 1822, to save the expense of their restoration! a piece of vandalism which destroyed the originality of the building and the _raison d'être_ for its nickname of "_l'Église aux Trois Clochers_." The building is 265 feet long, 65 feet broad, and 59 feet high. The nave is divided into five bays, the choir into four, and the apse into five; but these latter are much narrower than those of the nave. In the 17th century, the timber roof of Abbot Morard gave place to a stone vault, the transepts were rebuilt, and the nave much altered; but quite recently it has been restored to its primitive condition and decorated with frescoes by Hippolyte Flandrin. The church having been used during the Revolution as a saltpetre manufactory, the corrosive waters had so undermined the foundations of the pillars that they were obliged to be supported by enormous scaffoldings while the bases were repaired.