In pursuing this aim he was confronted by the champions of "liberty" and princely interests, who were represented at Constance by the Archbishop of Mainz and Frederick of Hapsburg, Count of Tyrol. The Archbishop, John of Nassau, had been prominent in effecting and prolonging the schism in the Empire. He was a firm supporter of John XXIII, and had no interest in attending the council except to thwart the designs of the King, whom he had been the last to accept. Frederick of Tyrol was the youngest son of that duke Leopold who had fallen at Sempach in the war with the Swiss. Of his father's possessions Frederick had inherited Tyrol and the Swabian lands, and the propinquity of his territories made him a powerful personage at Constance. His family was the chief rival of the house of Luxemburg for ascendency in Eastern Germany, and he himself seems to have cherished a personal grudge against Sigismund. To these enemies Sigismund could oppose two loyal allies, the elector palatine Lewis, who had completely abandoned the anti-Luxemburg policy pursued by his father, Rupert, and Frederick of Hohenzollern, the most prominent representative of national sentiment in Germany, who had already given in Brandenburg an example of that restoration of order which he wished Sigismund to effect throughout his dominions. Of the clerical members of the council the most prominent at the commencement was the pope John XXIII. He had been forced by his difficulties in Italy to issue the summons, but as the time for the meeting approached he felt more and more misgiving. His object was to maintain himself in office; but he was conscious that neither Sigismund nor the cardinals would hesitate to throw him over if he stood in the way of the restoration of unity. He therefore allied himself with Sigismund's opponents, the Elector of Mainz and Frederick of Tyrol, and spared no pains to bring about dissension between Sigismund and the council.