Its large westwork is framed by two differently-designed towers and other former abbey buildings abut the church, with the prefecture for Sarthe now occupying those on the south side.
It was restored and rebuilt around 1000 and the church was renamed Saint-Pierre de la Couture by bishop Sigefroi, who became a monk in the abbey and partly left abbot Gauzbert to take on his duties.
For most of the 11th century the church and the town experienced relative peace and prosperity, notably under the control and influence of abbot Anselin.
Building work on the church continued, forming an aisled nave, a transept and an ambulatory choir opening onto five side chapels.
These show figures from the Old and New Testaments and may be the first of their kind, before the Plantagenets popularized them throughout their lands in Maine and Anjou - previously column-statues were more common in doorways than interiors.
The first sculptures were carved in 1245 and many on the porch survive in good condition, including two angels, four prophets and eight virgins.