Though the Carolingian and later the Ottonian and Frantonian monarchs had been great patrons of architecture, and though important initial developments were made in Lombardy, it was in northern and central France that the greatest strides were made in the development of architecture in the eleventh century, and it was there that the style which we know as Romanesque reached its most brilliant function around 1100.
Romanesque reached its most brilliant function around 1100. The church at Charlieu is extremely impressive as it provides an admirable surface for a frescoed decoration, it is architecturally less progressive than the roof at Tournous, which in many ways heralds the groined vault and ribbed vault. These were to be the great glory of the fully developed Romanesque, for there also it was able to insert a window high up without weakening the support afforded by the side walls; though when seen from east or west the effect was produced of a continued vault not broken up in the way it is at Tournous.
There was, however, still to be much trial and judgement before this important architectural feature was fully developed, for though some Romanesque churches were roofed with barrel vaults, many of the great eleventh century buildings of France still had wooden roofs and staircase over the main aisles. But they were, in many cases divided into a series of bays by great spanning structures- diaphragm arches they are called-sometimes above a corresponding pair of piers and sometimes only at every other pair.