With the death of Henry V., which occurred in 1125, the Frankish or Salic Imperial line ended. For the Empire, though elective, had always a tendency to become hereditary and go in lines. If the last Kaiser left a son not unfit, who so likely as the son to be elected? But now a member of another family had to be chosen. The German princes elected Count Lothar von Supplinburg, Duke of Saxony. This departure was not without influence on the fortunes of Nuremberg. The question arose whether Nuremberg had belonged to the late Imperial house as private or imperial property. Did it now belong to the heirs of that house or to the newly-elected Emperor? In fact, part of the possessions, which had passed from the Salian Franks to the heirs, Conrad and Frederick, Dukes of Swabia, of the house of Hohenstaufen, was now demanded back by Lothar as being imperial property. Nuremberg was numbered among these possessions and became the head-quarters of the war which followed between the Kaiser and the two brothers. In 1127 the town had to stand another siege--this time of ten weeks' duration--whilst the Hohenstaufen brothers held it against Lothar. The siege was raised; but three years later the brothers had to give in. The Burg and town of Nuremberg were then given by the Emperor to Henry the Proud of Bavaria, a member of the great Wittelsbach family. He kept them till 1138, when Conrad having been elected King of the Germans, they went back in the natural course of things to the Hohenstaufen, who came once more to look upon the flourishing town as their own private property. It was to the above-mentioned Kaiser Conrad that the chronicles attribute the foundation of the monastery of St. Ægidius, on the site of the chapel, St. Martin's, which Charlemagne was reputed to have built. To Conrad also, with less show of likelihood, they ascribe the widening of the city. Widened the city has been more than once, as we can tell by the remains of walls and towers.[3] But the earliest fragment of these now extant--the lower part of the White Tower--dates only from the thirteenth century. It seems to have been the policy of the Hohenstaufen Kaisers to favour Nuremberg. They often held their court here. The greatest of them--the greatest and wisest of the Kaisers since Charlemagne--Frederick I. Barbarossa, to wit, lived in the castle in 1166. It was he, in all probability, who built the Kaiserliche Burg, and erected, over the Margaretenkapelle, the Kaiserkapelle, a grander and more splendid chapel of marble, which was certainly completed in the twelfth century. Of the remarkable Double Chapel thus constructed we shall have more to say later on. Meanwhile we must content ourselves with calling attention to the very similar Double Chapel at Eger in Bohemia. It was through Barbarossa that Nuremberg became connected with another of the great ruling families of the world.