This is the condensed history of the derivation of the style as generally accepted at the present day, though the subject has given rise to much controversy. The concentration of the weight of the vault upon the piers, instead of upon a continuous wall, was more or less the key to the whole scheme of Gothic construction; for the main principle remained the same throughout its many and varied examples. The idea was improved upon gradually and finally pushed to exaggeration; the decoration of the component parts of a building increased as the style advanced and they were reduced to just the sizes needed for stability, but their construction remained almost unaltered throughout. We have followed the steps by which the form given to Christian churches emanated from the early basilicas; this form of building, that is, its plan and divisions into nave, aisles, transept, choir, apse, etc., had become traditional and was generally accepted in all the best examples. [Illustration: PLAN OF RHEIMS CATHEDRAL.] The problem of accommodating large assemblies in the manner best suited to enable them to concentrate their sight and hearing upon a given point has been solved in various ways, perhaps most successfully in our modern opera-houses, but this problem was not one with which the Gothic architects endeavoured to grapple; their attention was devoted to the improvement and embellishment of the typical plan of structure, which custom and dogma had prescribed as the most suitable and in accordance with the needs of the liturgy. The plan was more or less elastic, and differed without material distinction in the different countries of Western Europe. These differences are easily noted by comparing the appended plans; the one, that of Rheims Cathedral, showing perhaps the most perfect arrangement of any in France, and the other, that of a typical English cathedral. The latter does not represent any particular structure, but is a composition including all the usual divisions and connecting buildings, taken from an old copy of Rickman. _a_, _a_, Towers at West end. _b_, _b_, Porches. _c_, The nave. _d_, _d_, Side aisles of the nave. _e_, The cloisters. _f_, Library. _g_, North transept. _h_, South transept. _i_, _i_, Side aisles of South transept. _k_, _k_, _k_, Chapels. _l_, Chapter house with passage from the cloisters. _m_, Central tower, cross or lantern. _n_, Screen, over which the organ is usually placed. _o_, Choir, at the east end of which the altar is usually placed. _p_, _p_, Side aisles of the choir. _q_, Lady chapel.