Political and religious alliance in 1531 at Smalkalden, in Hesse, among Protestant princes, after Emperor Charles V had ordered all the rulers of the empire who had embraced the Reformation to restore the ecclesiastical properties they had seized from the Catholics.
The League included six German princes, among them the notorious Philip of Hesse and the Elector John of Saxony; and eleven cities, including Strasbourg, Constance, and Bremen.
The alliance of foreign powers was solicited, and that of France was obtained in 1532.
Confident of the League's support, Protestant princes continued to suppress Catholic bishoprics and to confiscate Church properties.
In self defense, a Catholic League was formed at Nuremberg in 1538.
Dissolved after the defeat of Mühlberg (1547), the Smalkaldic League was restored after Charles V was obliged to sign the Treaty of Passau (1552), favorable to the rebels.
The next step was the Peace of Augsburg (1555), which marked the triumph of Protestantism in Germany.
New Catholic Dictionary