From this time onward the bishops' palaces increased greatly in size, their dimensions extending proportionately with those of the great cathedrals of the period. The importance of the episcopal buildings and their dependencies was on a par with the wealth and power of their owners. Some idea of their magnificence may be gathered from the private chapel of the archbishop at Rheims, which dates from the middle of the thirteenth century. [Illustration: 235. PALACE OF THE POPES AT AVIGNON. PLAN] The archbishop's palace at Albi has all the character of a feudal castle. Its buildings are protected by a keep, and encircled by walls and towers connected both with the ramparts of the city, and with that more important fortalice, the cathedral itself, the tower of which is, in fact, a formidable keep.[76] [76] See Part I., Cathedral of Albi, Figs. 70-73. The transformation of church and palace into fortresses by an elaborate system of defence was necessitated by the wars which ravaged the district, and from which Albi suffered more cruelly than any other town. The palace of the popes at Avignon which Pope Benedict XII. began to build in the fourteenth century, and the bishop's palace at Narbonne, are among the finest specimens of ecclesiastical fortification in the Middle Ages.[77] [77] For the Palace of the Popes, see Albert Lenoir and Viollet-le-Duc. The Popes, having established themselves at Avignon in the fourteenth century, built a huge mansion on the rock known as the _Rocher des Doms_, which overlooks the Rhone. In 1336 Benedict XII., having destroyed his predecessor's palace, laid the foundations of the immense fortified pile now in existence. The plans were the work of the French architect, Pierre Obrier. The building was added to by the successors of Benedict XII., Popes Clement VI., Innocent VI., and Urban V., and was completed, or at any rate made efficient for defence, by 1398, when Pedro de Luna, who became pope under the title of Benedict XIII., sustained a memorable siege therein. The whole building, which covers a very considerable area, was completed in less than sixty years. Its formidable mass was further strengthened by the fortified _enceinte_ of the town, some three miles in circumference. In general conception, in the architectural skill of its construction, and in its tasteful decoration, the Palace of the Popes at Avignon bears away the palm from all contemporary buildings in Germany and Italy, where French influences were paramount. [Illustration: 236. PALACE OF THE POPES AT AVIGNON. GENERAL VIEW] This noble monument is absolutely and entirely French. No finer combination of religious, monastic, military, and civil types could be desired in illustration of the art we have agreed to term _Gothic Architecture_, but which might be more truly entitled: _Our National Architecture in the Middle Ages_.