Following the abdication of Albert of Brandenburg, Walter von Cronberg became "Deutschmeister" in 1527, and later Administrator of Prussia and Grand Master in 1530. Emperor Charles V combined the two positions in 1531, creating the title "Hoch- und Deutschmeister", which also had the rank of Prince of the Empire. A new Grand Magistery was established in Mergentheim in Württemberg, which was attacked during the German Peasants' War. The Order also helped Charles V against the Schmalkaldic League. After the Peace of Augsburg in 1555, membership in the Order was open to Protestants, although the majority of brothers remained Catholic. The Teutonic Knights became tri-denominational, with Catholic, Lutheran and Reformed bailiwicks.