After the Second Italian War of Independence, much of northern Italy was unified under the House of Savoy's government; in the aftermath, Garibaldi's expedition of the Thousand overthrew the Bourbon monarchy in the Kingdom of the Two Sicilies. Afraid that Garibaldi would set up a republican government in the south, the Sardinians petitioned Napoleon for permission to send troops through the Papal States to gain control of the Two Sicilies, which was granted on the condition that Rome was left undisturbed. In 1860, with much of the region already in rebellion against Papal rule, Sardinia conquered the eastern two-thirds of the Papal States and cemented its hold on the south. Bologna, Ferrara, Umbria, the Marches, Benevento and Pontecorvo were all formally annexed by November of the same year, and a unified Kingdom of Italy was declared. The Papal States were reduced to the Latium region surrounding Rome, raising the Roman Question.