The building was begun in 1120 by Bishop Guy de Lons, and was sacked by the Protestants during the reign of Jeanne III of Navarre. It was restored in the 17th and 18th centuries. The apse, housing a pavement mosaic from the 12th century with hunting scenes, is in Romanesque style. In the interior, columns have capitals depicting histories of the life of Daniel, of the birth of Christ and the Sacrifice of Isaac.
Of the funerary monuments ordered by Henry II, subjected to iconoclastic damage by Protestants and to the collapse of the sanctuary vault in 1599, nothing remains. Archaeological excavations in 1928-1929 were successful however in rediscovering the royal crypt and the remains of its occupants.[2]