Louis XVI Executed — Republic Radicalizes

King Louis XVI is guillotined at the Place de la Révolution (now Place de la Concorde) after being convicted of treason by the National Convention. His execution shocks European monarchies and leads Austria, Prussia, Britain, and Spain to form the First Coalition against Revolutionary France. Queen Marie Antoinette is executed nine months later (October 16). The regicide marks the Revolution's irrevocable break with monarchy.