La Tosca is set against the background of the French Revolutionary Wars, the establishment of the Roman Republic, and its subsequent fall in 1799 when the French withdrew from Rome. Following the French withdrawal, Rome was controlled by the Kingdom of Naples, supported by the British and Austrians. However, the fighting continued elsewhere in Italy. The French troops had been defeated by the Austrians at the Siege of Genoa on 4 June 1800. Then on 14 June 1800, three days before the play begins, Napoleon's troops fought the Austrian forces at the Battle of Marengo. Although out-numbered, the French were ultimately victorious, despite early reports to the contrary. News of the surprise victory reached Rome on 17 June, the time setting for the play.