To define shortly, Gothic architecture is the art of erecting buildings with vaults whose ribs intersect (concentration of load) and whose thrusts are stopped by buttresses (the grounding of the thrusts). The never-ceasing downward and outward thrust of the vaulting is met by an equivalent resistance in pier and buttress and solid earth. Equilibrium results from that well-adjusted opposition of forces.
Since the starting point in the development of Gothic was the vaulting, and how to substitute a stone vault for a wooden roof was the germinal idea of the Romanesque builder, it is no digression to turn to the earlier school, the chrysalis of Gothic. The name "Romanesque" is an affair of yesterday, employed by a French archæologist about 1825. Various local designations had hitherto been used, such as Lombard, or Norman, or Romano-Byzantine, but the term Romanesque for this architecture is as suitable as the name Romance is for the popular languages which, in that same period, were forming out of the corruption of Latin. A definition given by M. Camille Enlart is excellent: "Romanesque art was a product of Rome, animated by a new spirit, and combined with a certain number of elements of barbarian or Oriental origin."
Rome gave the basilica plan to western Europe, which for centuries continued to build its churches as oblong halls with a small apse at one end. The hall, or nave, consisted of a central vessel with side aisles that were divided from it by piers. In the treatment of vaulting and the method of stone laying Romanesque architecture also derived from Rome. Byzantine influences certainly were important, but they affected the decoration more than the plan or the structure; the use of the Byzantine cupola was merely occasional. The Romanesque masters copied the ivories and miniatures of the Eastern Greeks till, in time, they turned to nature for their models, and then their work took on new life and evolved into the glory which is Gothic sculpture.
While some have laid stress on the Oriental influences, rather than those of Rome, in the formation of Romanesque art, others have overemphasized the personality and fantasy introduced into French architecture by the Barbarian invasions. No doubt the influx of new blood added new elements, but since knowledge of the invaders' art is fragmentary, there can be no scientific base for the theory. Composite, certainly, were the causes for the new spirit which animated architecture after the Carolingian day, but it is safe to say that the influence of Rome predominated.