We have already seen that that form of arch was first used in Provence as a constructional expedient, and not from any preference for the pointed form. The original idea may possibly have been derived from the Moors in Spain, amongst whom the pointed arch was common from early times, and was employed as a decorative feature. In Provence its use was limited to the vaulting, the round arch being preferred for all the ornamental parts of the architecture, and it continued to be so employed till the thirteenth century. It is a striking circumstance, observes Mérimée, that at the moment when the round arch was entirely abandoned in the North the pointed arch experienced the same disgrace in the South. In the North the pointed arch became the decorative form, when in the South the round arch was preferred. The position of the pointed arch is thus completely reversed in the North and in the South. The greater part of the vaulted constructions of the thirteenth century in the South are exclusively round, the advancement in skill, both in execution and in the use of materials, having rendered that form more generally available. Numerous examples of this employment of the round arch will be found in the following pages. The Roman and Byzantine influences were naturally strongest where the ancient remains and Eastern ornaments were most frequently met with. As we retire from the Mediterranean northwards and westwards the Roman buildings become less numerous and the signs of Byzantine commerce diminish. In those various countries different styles were naturally developed. These are divided by Viollet-le-Duc into the schools of Toulouse, Poitou, Auvergne, Burgundy, &c., all having distinct characteristics in plans, elevations, form of towers, ornament, sculpture, and every detail. Of these various schools the Burgundian was, during the twelfth century, in advance of all the others, not only in the size and magnificence of its buildings, but also as regards progress in design--efforts being there made to free the ornaments from the conventional and stereotyped patterns of classic art. Viollet-le-Duc endeavours to account for this advancement in Burgundian architecture by the suggestion that it possibly arose from the study of the paintings of Byzantine MSS., which were numerous in the monasteries, and therefore more frequently under the eyes of the monks than the purely architectural forms of buildings. These paintings preserve considerable freedom of treatment both as regards natural expression in the features and dramatic action in the figure, and are much less bound and fixed by traditional and conventional rules than the architectural forms and ornament.