Drei Bünde
Due to the weak 1526 treaty, in 1531 Milan attacked again, capturing Morbegno and defeating the League forces in the area. The Three Leagues called the Old Swiss Confederacy for help, calling in duties of a defence alliance concluded earlier. Due to the religious conflicts in the Confederation only the Protestant cantons supported the Three Leagues, while the Catholic cantons insisted that any help was dependent on the Leagues converting back to the old faith. The Protestant and League forces were able to drive the Milanese out of the Valtellina. In a peace treaty concluded the next year, Chiavenna and the Valtellina were granted to the Three Leagues; only the "tre pievi" came under the supervision of Milan.