The great expansion following the fears of the first Millenium was the motor behind the major building projects. The present Romanesque church construction site started under the guidance of Abbot Odolric (1031-1065), on the actual setting of a 10th century basilica. The first campaigns of work concerned the lower parts of the apse and the minor apses, using the special red sandstone from Combret quarry, in the Dourdou valley. This material, probably considered too friable, was not used again in the new project led by Abbot Etienne II (1065-1087), who continued the work towards the west side. The "rousset", a beautiful bright yellow limestone extracted from the Lunel plateau, was then generally preferred. Its warm key tones balanced the local gray schist, used in the masonry as filling material wherever a cut stone was not necessary. The great Abbot Bégon III, head of the abbey for twenty years (1087-1107), led an intense period of construction, including the church tribunes and the cloister. The role of his follower, Abbot Boniface (1087-c.1125), is uncertain. No document specifically indicates it. The vaulting of the church and the construction of the western facade were probably achieved under his governance.
The Romanesque cupola of the lantern tower, built too quickly above the crossing, collapsed at an unknown date. The consolidation works, carried out in the 1980s by the Historical Monuments architects, allowed better understanding of the different stages of construction, the changes and problems. The main weaknesses came from the conical vaults principally meant to pass from a square to a circular plan. The cupola was rebuilt during the second half of the 15th century, with a deliberate choice of Gothic vaulting. A century later, in 1568, the abbey-church almost collapsed after a blaze set by the Protestants. The big choir columns, about to collapse after the intense fire, were held in place by iron braces and contained in a sustaining wall of masonry. During this attack, the front towers knocked off, as was the central bell tower. It has been rebuilt since, with an extra level and crowned with a framed spire, to give its present look.
Starting in 1837, restoring the church became possible, after the involvement of Prosper Mérimée. At that time, he was Inspector for the Historical Monuments. The church was then in a pitiful condition, largely abandoned since the Revolution years. His long and detailed memoir, addressed to the Ministry, allowed him to obtain the classification of an edifice and a necessary grant. Etienne Boissonnade, the Arts Departments architect, became responsible for the restoration works, starting with the most urgent. In 1874, the Arts Departments ordered a complete restoration project by the architect Jean-Camille Formigé. The masterpiece to be realized was considerable: the reconstruction of the choir colonnade and vaults, etc. Later on, in 1881, the elevation of the front towers was started, closely followed by their covering with the present heavy pyramidal stone roofs.