The pointed arch is above referred to at Kelso[8] as having been introduced, along with Norman elements, at the crossing under the tower, where its strength was considered useful. The pointed arch, however, cannot generally be said to have been adopted in Scotland in consequence of any special requirement of construction; it rather followed the lead of countries further south as a matter of fashion. Few of our early churches were vaulted throughout at the beginning of the thirteenth century, and the forms of such vaults as existed were, doubtless, borrowed from England. The vaults of the choir of St. Andrews Cathedral and the lower church of Glasgow Cathedral are probably the only exceptions, most of our other large churches having been vaulted, if vaulted at all, at a later period. The large churches were generally designed to have the side aisles only vaulted, the central aisle being covered with a wooden roof, as, for example, Arbroath Abbey and Dunblane and Elgin Cathedrals. Holyrood Abbey is an exception; but there the vaulting of the central aisle was sexpartite, and the pointed arch was not much required. The first pointed style, when introduced into this country, speedily spread, and most of our large churches are built in that style. Many monasteries, as we have seen, were founded in the time of the sons of Queen Margaret; but most of these appear to have been at first on a small scale, and were chiefly rebuilt on a larger plan, together with new monasteries, in the thirteenth century. Such are the abbeys of Holyrood, Inchcolm, Kilwinning, Pluscardine, Culross, and Beauly. The thirteenth century was also distinguished as the great epoch for the erection of cathedrals. The secular clergy had then risen to power, and, under their guidance, the erection of magnificent cathedrals, both at home and abroad, was the principal architectural phenomenon of the period. In France and England the great majority of the cathedrals owe their origin or completion to about this epoch; and in Scotland there were erected, in whole or part, during the first pointed period, the cathedrals of St. Andrews, Dunblane, Glasgow (the choir and crypt), Elgin, Brechin, Dunkeld, Caithness, the choir of St. Magnus’ in Orkney, and Galloway. The first pointed style, in which all the above structures were carried out, reached Scotland, as already mentioned,[9] through England. The relation between the ecclesiastics of the two countries was then very close, the monasteries being colonised from English houses, and the cathedral rules being based on the uses of those of England.