Henry's hopes were now turned to his younger son, Henry, who was of a cold, calculating, treacherous disposition. The political and religious foes of the Emperor were still actively scheming for his overthrow, and they succeeded in making the young Henry their instrument, as they had made his brother Konrad. During the long struggles of his reign, the Emperor's strongest and most faithful supporter had been Frederick of Hohenstaufen, a Suabian count, to whom he had given his daughter in marriage, and whom he finally made Duke of Suabia. The latter died in 1104, and most of the German princes, with the young Henry at their head, arose in rebellion. For nearly a year, the country was again desolated by a furious civil war; but the cities along the Rhine, which were rapidly increasing in wealth and population, took the Emperor's side, as before, and enabled him to keep the field against his son. At last, in December, 1105, their armies lay face to face, near the river Moselle, and an interview took place between the two. Father and son embraced each other; tears were shed, repentance offered and pardon given; then both set out together for Mayence, where it was agreed that a National Diet should settle all difficulties. On the way, however, the treacherous son persuaded his father to rest in the Castle of Böckelheim, there instantly shut the gates upon him and held him prisoner until he compelled him to abdicate. But, after the act, the Emperor succeeded in making his escape: the people rallied to his support, and he was still unconquered when death came to end his many troubles, in Liege, in August, 1106. He was perhaps the most signally unfortunate of all the German Emperors. The errors of his education, the follies and passions of his youth, the one fatal weakness of his manhood, were gradually corrected by experience; but he could not undo their consequences. After he had become comparatively wise and energetic, the internal dissensions of Germany, and the conflict between the Roman Church and the Imperial power, had grown too strong to be suppressed by his hand. When he might have done right, he lacked either the knowledge or the will; when he finally tried to do right, he had lost the power. [Sidenote: 1099.]