After the crushing Piedmontese defeat at the Battle of Novara on 23 March 1849, Garibaldi moved to Rome to support the Roman Republic recently proclaimed in the Papal States. However, a French force sent by Louis Napoleon threatened to topple it. At Mazzini's urging, Garibaldi took command of the defence of Rome. In fighting near Velletri, Achille Cantoni saved his life. After Cantoni's death, during the battle of Mentana, Garibaldi wrote the novel "Cantoni the Volunteer".