In 1077 the bishop of Clermont, at the request of Seigneur Archambault II, gave the church of Besson, then probably a priory, to the prior of Saint-Pourçain. Major construction work probably began soon thereafter. The central tower, which had imposed significant deformation on the body of the church, was struck by lightning in 1620 and in 1700 the tower, choir and north transept collapsed. The western crossing piers were rebuilt, together with vaults of the crossing, transept and apses. The nave vault of plaster and brick was installed towards 1870 replacing a wooden roof which had been installed after the failure of the pointed barrel vault. These repairs, which included the casing of the interior of the northern lateral apse with new masonry (and pointed framing arches), render it hard to read the chronology of construction in the critically important middle part of the church. There are three obvious anomalies. First, the elegantly articulated and sumptuously decorated central apse of ashlar is flanked by earlier-looking lower lateral apses of petit appareil. Second, the roof line of the transept arms are oddly asymmetrical, rising sharply to the west. And third, the transept arms are much lower than the nave and there is an obvious suture where the west side of the south transept arm adjoins the south nave aisle. These anomalies are explained by the following scenario. An older church with nave, transept and three apses was modified soon after 1100. First, the original central apse was demolished and the present ashlar apse inserted, leaving the older lateral apses and transept arms in place. And second, the older nave was replaced by the present four-bay barrel vaulted nave with adjoining groin vaulted aisles. The lateral chapels were used by local seigneurial families: the southern chapel communicates with the central apse by means of a viewing aperture. Sumptuous portals of the mid-twelfth century pierce the eastern bay of the south nave aisle and the western frontispiece. Continuing structural problems are caused by the site of the church on a southern slope and the tendency of the western wall to detach from the body of the church.