in 772–780, but this area resisted and the war with the Saxons lasted for about thirty years. Charlemagne ended the Germanic custom of an itinerant court moving from place to place and established a real capital. As he was ageing, he decreased the frequency of military expeditions and, after 806, virtually did not leave Aachen. Aachen's geographic location was a decisive factor in Charlemagne's choice: the place was situated in the Carolingian heartlands of Austrasia, the cradle of his family, East of the Meuse river, at a crossroads of land roads and on a tributary of the Rur, called the Wurm. From then, Charlemagne left the administration of the Southern regions to his son Louis, named King of Aquitaine, which enabled him to reside in the North. Besides, settling down in Aachen enabled Charlemagne to control from closer the operations in Saxony. Charlemagne also considered other advantages of the place: surrounded with forest abounding in game, he intended to abandon himself to hunting in the area. The ageing emperor could also benefit from Aachen's hot springs. The scholars of the Carolingian era presented Charlemagne as the "New Constantine"; in this context, he needed a capital and a palace worthy of the name. He left Rome to the Pope. The rivalry with the Byzantine Empire led Charlemagne to build a magnificent palace. The fire that destroyed his palace in Worms in 793 also encouraged him to follow such a plan. Importance of the project entrusted to Odo of Metz Historians know almost nothing about the architect of the Palace of Aachen, Odo of Metz. His name appears in the works of Eginhard (c. 775–840), Charlemagne's biographer. He is supposed to have been an educated cleric, familiar with liberal arts, especially quadrivia. He had probably read Vitruvius' treatise on architecture, De Architectura. The decision to build the palace was taken in the late 780s or the early 790s, before Charlemagne held the title of emperor. Works began in 794 and went on for several years. Aachen quickly became the favourite residence of the sovereign. After 807, he almost did not leave it any more. In the absence of sufficient documentation, it is impossible to know the number of workers employed, but the dimensions of the building make it probable that there were many of them. The geometry of the plan chosen was very simple: Odo of Metz decided to keep the layout