Why did Camillo Benso, count di Cavour order the invasion of Umbria and the Marche in 1860?

In 1860, Camillo Benso, count di Cavour, ordered the invasion of Umbria and the Marche primarily to maintain political control over the Italian unification movement, known as the Risorgimento.2

Cavour was concerned that the revolutionary, republican forces led by Giuseppe Garibaldi—who had successfully conquered the Kingdom of the Two Sicilies—might attempt to march on Rome. Cavour feared that such an attack on the Vatican would provoke international intervention, particularly from France, and undermine the moderate, monarchist leadership of Piedmont-Sardinia.123

By invading the papal territories, Cavour aimed to:
* Check Garibaldi’s advance: He sought to intercept the revolutionary forces and ensure that the unification process remained under the authority of the Piedmontese crown.12
* Assert diplomatic legitimacy: Cavour positioned himself as a defender of law and order against revolutionary excess, while simultaneously using the threat of Garibaldi’s potential attack on Rome as a justification to Napoleon III for the military intervention.13
* Consolidate the nation: The move allowed Piedmont to weld the northern and southern territories into a single, unified kingdom.12