Two years later, the second war of Kappel broke out. Zürich was taking the refusal of the Catholic cantons to help the Grisons in the Musso war as a pretext, but on 11 October 1531, the Catholic cantons decisively defeated the forces of Zürich in the battle of Kappel am Albis. Zwingli was killed on the battlefield. The Protestant cantons had to agree to a peace treaty, the so-called "Zweiter Kappeler Landfriede", which forced the dissolution of the Protestant alliance ("Christliches Burgrecht"). It gave Catholicism the priority in the common territories, but allowed communes that had already converted to remain Protestant. Only strategically important places such as the Freiamt or those along the route from Schwyz to the Rhine valley at Sargans (and thus to the Alpine passes in the Grisons) were forcibly re-Catholicised. In their own territories, the cantons remained free to implement one or the other religion. The peace thus prescribed the "Cuius regio, eius religio"-principle that would also be adopted in the peace of Augsburg in the Holy Roman Empire in 1555. Politically, this gave the Catholic cantons a majority in the "Tagsatzung", the federal diet of the confederacy.