League of Schmalkalden

The Schmalkaldic League (English: /ʃmɔːlˈkɔːldɪk/; German: Schmalkaldischer Bund; Latin: Foedus Smalcaldicum or Liga Smalcaldica) was a defensive military alliance of Lutheran princes within the Holy Roman Empire during the mid-16th century. Although originally started for religious motives soon after the start of the Reformation, its members eventually intended for the League to replace the Holy Roman Empire as their source of political allegiance. While it was not the first alliance of its kind, unlike previous formations, such as the League of Torgau, the Schmalkaldic League had a substantial military to defend its political and religious interests. It received its name from the town of Schmalkalden, which is located in modern Thuringia.

The League was officially established on 27 February 1531, by Philip I, Landgrave of Hesse, and John Frederick I, Elector of Saxony, the two most powerful Protestant rulers at the time. It originated as a defensive religious alliance, with the members pledging to defend each other should their territories be attacked by Charles V, the Holy Roman Emperor. At the insistence of the Elector of Saxony, membership was conditional on agreement to the Lutheran Augsburg or Tetrapolitan Confessions. This solidified the dominance of Lutheranism in Germany to the exclusion of Zwinglianism, which had had some adherents.

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