century were the sources from which the Normans derived a large share of their architectural inspiration. A comparison of the Church of San Michele of Pavia with that of the Abbaye-aux-Hommes of Caen would alone suggest this, even if we did not know that Lanfranc, who was Abbot of the Monastery when this church was building, had come from Pavia. The rudimentary principles of structure embodied in the churches of Lombardy seem to have been thus transmitted to the North, where they were rapidly developed, so that from San Michele of Pavia to the Cathedral of Amiens a logical and progressive series of changes may be traced.
Gothic architecture is thus in no sense an independent, though it is a distinct style. And hence it is not strange that the finest Gothic buildings should retain, as they do, many traces of the Romanesque elements out of which they were evolved. It is a mistake to suppose with M. Colfs that such lingering of older elements necessarily marks a building as wanting in Gothic character. On the contrary, such elements are natural to Gothic, which is an art not only derived from Romanesque, but which is Romanesque recreated. Every constructive member of a Gothic building exists, in rudimentary form, in a vaulted Norman building. Even the osseous system which distinguishes Gothic exists there in potency. But the creative principle of the new style is not in Norman art yet recognised, and the structural system does not yet frankly and independently exercise its functions.
It may help us to gain a more complete idea of Gothic briefly to review some of the steps in the process by which the transition was effected. And we may advisably begin with the first principles of arched construction.
I have already alluded to the fact that a new principle was introduced into the art of building when the arch exerting side thrusts was first employed. The most effective way to meet such thrusts is by some kind of external abutments. But the thrusts of arches may also be neutralised by downward pressure upon the walls where they operate. Both methods were employed by the Romans and by the Romanesque builders, as well as by the Gothic architects. In the case of a simple arched opening in a wall the thrusts are, of
