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How did the second Defenestration of Prague contribute to the Thirty Years’ War?

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Prague Prague on the banks of the Vltava River.

The second Defenestration of Prague served as the immediate catalyst for the Thirty Years’ War by signaling the start of a militant Bohemian revolt against Habsburg authority.12

On May 23, 1618, Protestant estates in Prague held an assembly at Prague Castle to address the violation of religious liberties guaranteed by the Letter of Majesty. After finding two imperial regents, William Slavata and Jaroslav Martinic, guilty of these violations, the assembly threw them and their secretary from a castle window.12

This act of defiance prompted the Bohemian estates to establish a new government and assemble troops, while the future emperor Ferdinand II prepared for military retaliation. The conflict escalated as the Bohemian estates elected the Calvinist Frederick V as their king, drawing in international alliances and setting the stage for the large-scale military actions that defined the war.32