The Siege of Rome occurred from 9 February to 3 July 1849 when the army of the French Second Republic, commanded by Charles Oudinot, captured the city of Rome from the revolutionary Roman Republic and restored the city to the Papal States.
In February 1849 Italian radicals declared a Roman Republic, deposing Pope Pius IX as ruler of the city. The king of Naples and French president Louis Napoleon - the future emperor Napoleon III - sent troops to reinstate the Pope. The Republic installed a ruling triumvirate, including the famous Italian nationalist Giuseppe Mazzini, to organize the defense of the city. On 27 April they were joined by Giuseppe Garibaldi's legion, a force of irregulars armed with muskets, lances, and daggers. Garibaldi's imposing presence inspired the defenders, who prepared to defend Rome against the French army under General Charles Oudinot. On 29 April an initial French infantry assault was repulsed; the forces of the king of Naples were equally driven off. After a month's passive siege, the French resumed the battle for the city on 3 June. A final assault broke through the defenses on the night of 29-30 June. Garibaldi led 4,000 volunteers out of the city before the French formally entered on 3 July.