Ferdinand II

Ferdinand II was elected Holy Roman Emperor in Frankfurt, succeeding his cousin Matthias. His election was contested by the Protestant Union, which supported Frederick V of the Palatinate. Ferdinand's staunch Catholicism and determination to suppress Protestantism set the stage for the Thirty Years' War.

Ferdinand II's Catholic forces, led by General Tilly, decisively defeated the Protestant Bohemian army at the Battle of White Mountain near Prague. This victory crushed the Bohemian Revolt and allowed Ferdinand to reassert Catholic control over Bohemia. The battle was a key early event in the Thirty Years' War.

Ferdinand II issued the Edict of Restitution, which ordered the return of all church lands seized by Protestants since the Peace of Augsburg (1555). This aggressive Catholic policy alienated many Protestant princes and led to the intervention of Sweden in the Thirty Years' War. The edict was a major cause of the war's escalation.

Ferdinand II's imperial forces, under General Tilly, besieged and sacked the Protestant city of Magdeburg. The city was destroyed, and an estimated 20,000 inhabitants were killed in the massacre. The sack of Magdeburg became a symbol of the brutality of the Thirty Years' War and galvanized Protestant resistance.

Ferdinand II signed the Peace of Prague with the Protestant Elector John George I of Saxony, ending the war between the Emperor and many German Protestant states. The treaty modified the Edict of Restitution and granted amnesty to most Protestant princes. However, it did not end the broader Thirty Years' War, as Sweden and France continued fighting.