In 1351 Zurich followed suit. Her clever and powerful burgomaster, Brun, was keenly desirous of raising her to greatness. He was less regardful of the interests of the Eidgenossen, and indeed had strong leanings towards Austria and the empire, as affording a wider scope for ambitious politics. Consequently he would not permit her superior position as an imperial free city, nor her foreign and commercial relations, to be injured by submission to the Forest control, and he carried a clause which left her free to join in any other alliances she choose, provided that with the Waldstätten was not broken. He also bound the Forest states by treaty, to secure to Zurich its own constitution. The documents connected with this alliance show that the five states formed a power quite ready to cope with Austria. And well for them that they were so ready. Louis of Bavaria, the protector of the Forest Cantons, was dead, and his successor on the German throne was Charles IV., son of the famous blind King of Bohemia, who fell so bravely at Cressy. To maintain his authority Charles fell back on the friendship of Austria, and to win the favour of Albrecht (the "Wise," or "Lame"), he nullified all the measures which Louis had enacted against Austria, measures which had destroyed the power of that country in the Waldstätten. The destruction of Rapperswyl[28] (Zurich), and the union between Zurich and the other four states were regarded by the Habsburgs as a challenge, and gave rise to a long-protracted war, marked rather by feats of diplomacy on the part of Austria than by feats of arms. Albrecht was desirous of having a reckoning with the Eidgenossen generally, yet for the present he confined his attacks to Zurich, their strongest outpost. The assault by sixteen thousand men in 1351 was stoutly opposed, and collapsed suddenly by proffers of peace. Queen Agnes of Königsfelden, the duke's sister, was called in as umpire, and Brun temporizing with Austria to save his town, a verdict was passed so injurious to the people of the Forest, that they refused the mediation of this "wondrously shrewd and quick woman," who had for these thirty years swayed the Habsburg politics, and the quarrel broke out anew.