In central Italy, Piedmont-Sardinia invades the Papal States
The Papal States refused Count Cavour's demands to disband its foreign volunteers and accede to the demands of nationalist insurrectionists and 32,000 Piedmontese troops crossed into Rome-controlled areas of central Italy. Cavour's aim, with tacit French approval, was to forestall further advances by Garibaldi, link up with him in the south, and to unite Italy under his king, Victor Emmanuel II. (By John Osborne)
Peter N. Stearns, William Leonard Langer (eds.) An Encyclopedia of World History: Ancient, Medieval, and Modern ... (New York: Houghton Mifflin, 2001), 498.