We have now briefly to review the changes produced in the plan of the cathedral. There were those effected as an immediate consequence of the fire, and others which were more the result of the continued energy of the thirteenth-century builders. The most remarkable one was that which converted the French chevet, or group of apses, into the more familiar square, and characteristically English, eastern termination. The apsidal chapels on the east side of each arm of the transept had disappeared to make room for others of a different shape and size. The other chapels at the east remained the same in number; but towards the close of the thirteenth century the lady-chapel had been lengthened, and the aisles of the choir, being continued eastward, ended in small chapels to the north and south of the central one. The other changes were those caused by the addition of chapels off the south and north aisles of the nave. The addition of the south and north porches, and the sacristy next to the south arm of the transept, were the only other alterations, if we except the addition of buttresses, which had been made in the original arrangement up to the beginning of the fourteenth century. [Illustration: THE CATHEDRAL FROM THE SOUTH-EAST, ABOUT 1836. _From Winkles's Cathedral Churches_.] Though the quest may not be followed here, it would be interesting to try and trace the cause of this desire to add chapels to mediæval buildings. It had during the thirteenth century already become a clear indication of that gradual movement affecting the arrangement of churches which originated in the introduction of new doctrinal ideas. The particular set of ideas which caused such additions as these had now become a part of the common property of popular thought, imagination, and reverent superstition. The earlier designers and builders had not been taught to consider these features essential to the complete equipment of a church planned in accordance with primitive usages; they were a simple example of the influence which doctrine exercised upon the history of art and the scope of archaeological inquiry.