At the time the League had grown so strong, Duke Albrecht the Second ruled in Austria and enjoyed the friendship of the Emperor Charles the Fourth, of the house of Luxemburg. In preparing for a struggle with the League he had strengthened his castles and cities and had assured himself of the loyal service of his vassals. The war, however, was confined to pillaging expeditions and petty encounters which did the League little harm, and at last an unconditional peace was made between the two parties. After Albrecht’s death, his oldest son, Rudolph the Fourth, succeeded. This prince, the first of his house to receive the title of archduke, had the hereditary Hapsburg spirit and strove to the utmost to extend the supremacy of the empire. Notwithstanding the Emperor Charles was his father-in-law, he opposed him by every kind of artifice and continually interfered with his plans. He strengthened himself by alliances with neighboring powers, especially with Basle and other imperial cities, and weakened the Emperor’s power in Italy. By the marriage of his brother Leopold to the daughter of Bernabo Visconti of Milan he secured the adherence of many noble Italian families. He appointed Brun, the Zurich burgomaster, a member of his privy council and thus attached him to his interests. He drove in a wedge between Lake Zurich and Schwyz, by the purchase of territory, and to secure control of the commercial highway from Italy to Germany he built a bridge across the lake upon the pretext of shortening the route for pious pilgrims on their way to retreats. While engaged in these various enterprises the prince died in his twenty-sixth year and was succeeded by his brother Leopold, in 1365.