See Delius, Untersuchungen fiber die Geschichte der Harzburg (Halberstadt, 1826); Dommes, Harzburg and seine Umgebung (Goslar, 1862); Jacobs, Die Harzburg and ihre Geschichte (1885); and Stolle, Fiihrer von Bad Harzburg (1899).
In 1069 he was recalled by Henry, when he made a further attempt to establish a northern patriarchate, which failed owing to the hostility of the papacy and the condition of affairs in the Scandinavian kingdoms. He died at Goslar on the 16th or 17th of March 1072, and was buried in the cathedral which he had built at Bremen.
Robineau (Saint-Omer, 1882); and Friedrich Koch (Goslar, 1885).
The league was soon joined by other strong cities, among them Strassburg, Ulm, Constance, Lhbeck and Goslar; but it was not until after the defeat and death of Zwingli atKappel in October 1531 that it was further strengthened by the adhesion of those towns which had hitherto looked for leadership to the Swiss reformer.