Ferdinand II of the Two Sicilies is succeeded by his twenty-three-year-old son, Francis II, on May 22, 1859.

New plebiscites in the duchies and the Papal Legations reconfirm popular sentiment in favor of union with Piedmont.

It is fear of a democratic revolution, the need to weaken Austria, and England's desire to set up a strong Italian state as a counterweight to French influence that induce the European powers to assist the Piedmontese monarchy in obtaining this great success.

Modena, Parma, Romagna and Tuscany vote in referendums for union with Sardinia-Piedmont on March 5, 1860.

This alarms Napoleon III, who fears a strong Savoyard state on his south-eastern border and he insists that if the Kingdom of Sardinia is to keep the new acquisitions they will have to cede Savoy and Nice to France.

This is done after referenda shows over 99.5% majorities in both areas in favor of joining France.

Victor Emmanuel now secretly encourages the revolutionary general Giuseppe Garibaldi to conquer Sicily and Naples.

The Italian democratic movement refuses to acknowledge that the national revolution is in any way complete so long as parts of the peninsula remain under the old sovereigns.

Sicily, where autonomist opposition to the Bourbon government is endemic and extreme, is the most obvious place for a democratic revival.

A Mazzinian-inspired insurrection, the Gancia revolt, had broken out in Palermo on April 4, 1860, and spread throughout the island, but it had quickly been quelled.

Sicilian democrats give evidence after the Gancia revolt that they can overcome their deep divisions of ideology and class.

In May, they have the opportunity to assist Garibaldi's Expedition of the Thousand, a volunteer force that had set sail from Genoa on the sixth to free the Italian south from Bourbon rule.

Garibaldi's volunteers, with scant preparations and a shortage of weapons, land at Marsala on May 11, 1860.

Garibaldi’s thousand “Red Shirts” defeat the regular troops of the king of Naples at the Battle of Calatafimi on May 15, then ...

...take advantage of a popular uprising to capture Palermo, the capital of Sicily, on May 27.

The forces of Garibaldi defeat royal Neapolitan forces near Messina in the Battle of Milazzo on July 20, 1860, bringing nearly all of Sicily under Garibaldi's control.

The new king of the Two Sicilies, Francis II, grants a constitution and promises amnesty to Sicilian rebels as the European powers attempt mediation.

At this point, without the consent of Victor Emmanuel II and perhaps even against his wishes, Garibaldi had crossed the Straits of Messina on August 22, 1860, with the assistance of the British Navy and ...

...makes a triumphant entry into Naples by September 7.

King Francis flees to Capua.

Garibaldi's forces overcome the last organized army of the Bourbons at the Battle of Volturnus, near Caserta, on October 1.

After this battle, the largest by Garibaldi's expedition, both sides seem exhausted.

In the immediate aftermath, the battle is a defeat for Garibaldi, but in the longer term, it proves to their advantage.

The cost for Garibaldi in men is higher: 506 killed and 1,389 taken prisoner, but the Neapolitan forces has lost 308 and 2,507 taken prisoner.

The Bourbon army is unable to use their victory to capture Caserta.

Both armies showed bravery, except perhaps for the Royal Guards and troops of Ruiz de Ballesteros, who are the largest cause of the defeat.

Garibaldi is forced to request troops from the Piedmontese.

Yet while Francesco II wishes to use the impasse for the Garibaldi forces to attack again, his generals recommend hat the troops be reorganized.

Thus he leaves Capua for Gaeta, and will be unable to retake his throne.

Soon Piedmontese reinforcements will arrive, defeating the Royal troops at Gaeta, and causing the King to flee.