Count Cavour of Piedmont had long been suspicious of Garibaldi and with the "Redshirts" controlling Naples, he was forced to take action. He had decided as early as August 1860 to invade the Papal States and link up with Garibaldi in the south with the aim on uniting Italy under his king, Victor Emanuel II. With tacit French approval, and on the pretext of a nationalist uprising in the Papal States, Cavour set events in motion with an ultimatum to Rome. (By John Osborne)
Source Citation
Peter N. Stearns, William Leonard Langer (eds.) An Encyclopedia of World History: Ancient, Medieval, and Modern ... (New York: Houghton Mifflin, 2001), 498.