The Norman style of architecture continued to prevail in England till near the close of the twelfth century, and in Scotland for some time thereafter. At that period a further and completer development awaited the architecture of the Middle Ages. We have seen that the “subordination” of all the parts had been achieved, together with the use of the groined vault, with its accompanying buttresses and pinnacles, in the round arched style. The employment of the round arch was, however, found to involve many practical difficulties in connection with the vaulting. The bays of the nave, so long as they were _square_ in plan, could be conveniently vaulted with intersecting semi-circular groins; but when they were of an oblong form, the width being greater than the length (as was often found necessary in order to suit the vaulting of the side aisles), the round arch was found very inconvenient in consequence of the large arch which spanned the nave rising to a greater height than the smaller arch of the side walls. It was endeavoured to overcome this difficulty by stilting the arch of the side vault so as to make its apex of the same height as the main transverse vault; but this scheme interfered with the lines of the groins or intersection of the vaults in such a manner as to render it unworkable. It therefore became necessary to seek for a more flexible form of arch, which would enable the apex of all the arches of the vaults, whatever their span, to rise to any required height. This useful form was discovered in the pointed arch, which had long been in use in Provence, and which the builders of the North of France now found themselves forced to adopt by the exigencies of their vaults, and which ultimately led to the development of the pointed style. The new life and growth of architecture which, as we have seen, sprung into existence in the twelfth century, had been adopted with eagerness by the builders of the Royal Domain of France. Not being trammelled by the traditions of an ancient and long-used system, these architects had thrown themselves with energy into the new development of architecture, and it was in this locality that the application of the pointed arch to the difficulties of the vaulting seems to have been first successfully carried out.