The Piedmontese campaign in central Italy took place between September and October 1860 during the unification of Italy. It followed the Second Italian War of Independence and the Expedition of the Thousand. The campaign saw a military contingent from the Kingdom of Sardinia (Piedmont) sent against the Papal States. Later, the operation was extended to the Kingdom of the Two Sicilies, officially to restore order and prevent Garibaldi's army from proclaiming an independent republic and moving against the Pope.
The invasion of the Papal States
In the first phase of the campaign the Piedmontese army, composed of the IV and the V Army Corps under General Manfredo Fanti, moved towards the papal provinces of Umbria and the Marche. The casus belli was the need for Piedmont to intervene against the papal army’s repression of the revolutionary movements that favoured the unification of Italy. These had broken out in the first days of September in conjunction with Garibaldi's entry into Naples. The papal forces also included foreign volunteers and mercenaries, commanded by generals from beyond the Alps, and these facts were also used as a justification for the campaign. The Piedmontese plan was for a pincer movement: its armies were to move forward in either side of the Apennines, interrupting the communication routes between Lazio, Umbria and Marche, and then converge on Ancona, the final objective of the expedition. On 11 September 1860 the Piedmontese army crossed the borders of the Papal State at three different points: the V Army Corps, commanded by Fanti himself, passed through Arezzo and Sansepolcro and took Perugia on 14 September before headed towards Foligno. The IV Army Corps invaded the Marche from two points: the 13th Division, under the command of Raffaele Cadorna, followed a route close to the Apennines through Urbino, Cagli and Gubbio, while the rest of the contingent, composed of the 4th and 7th Divisions under Enrico Cialdini proceeded along the coast by way of Pesaro, Fano and Senigallia, clashing with the Papal Army of General de Lamoricière at the battle of Castelfidardo on 18 September. Having taken control of the Via Flaminia and Via Salaria, the Piedmontese took the main cities of Umbria and the Marche and routed the papal contingent that was trying to gather near Macerata. They then besieged Ancona, taking it on 29 September, thanks to a successful naval blockade.
The invasion of the Kingdom of the Two Sicilies
The second phase began with the Piedmontese invasion of the Kingdom of the Two Sicilies. The rationale was both to restore order following the effective collapse of the government of Francis II and to prevent Garibaldi from completing the conquest of the kingdom after the Battle of the Volturno, and then attacking Rome.
=== On the march south === Arriving in Ancona on 3 October, King Victor Emmanuel took command of the army and marched south at the head of his troops, aiming to reach the Volturno plain, where the Bourbon army, entrenched between the strongholds of Gaeta and Capua, was defending itself from Garibaldi's men. While a contingent moved along the coast by ship, the bulk of the army set out along two different routes; as they advanced, insurrections and mutinies broke out in various cities and fortresses not yet occupied by Garibaldi's men, and groups of volunteers began to gather. On 12 October Victor Emmanuel crossed the Tronto River with his troops. At the same time, part of the army moved towards Spoleto and Rieti with the intention of reaching L'Aquila. After bypassing the fortress of Civitella del Tronto, which was subsequently placed under siege, the king continued along the coast to the mouth of the Aterno and finally headed towards Chieti. Once in Popoli, the two contingents reunited and together headed towards Roccaraso and Castel di Sangro, in the direction of the Macerone pass where the road from Abruzzo passed that allowed access to the Terra di Lavoro. Here the Piedmontese were joined by the troops who had departed from Ancona and, having landed in Manfredonia, had moved along a route that had taken them to Foggia, Ariano and Benevento. The main military events of this phase were the siege of the fortress of Civitella, which began on 26 October and lasted several months, and the battle of Macerone (20 October) which, although considered a simple skirmish due to the small forces on the field, opened the way for the Piedmontese, allowing them to take the Bourbon army from behind.
=== On the battlefield === The Piedmontese objective was to join up with Garibaldi's southern army against the army of the Two Sicilies in the northern portion of the Terra di Lavoro. King Francis II had retreated to the fortress of Gaeta, maintaining control of an area that was protected by a series of defensive lines, the most important of which ran along the northern bank of the Volturno River, from the coast to the fortified city of Capua. Having failed in the Battle of the Volturno to repel Garibaldi's men, Francis II's army was forced to retreat further by the intervention of the Piedmontese army, which had reached the rear of the Bourbon defensive line. Defeated in the Battle of San Giuliano, the Neapolitan army was forced to abandon Capua and retreat to the Garigliano line. The final event of the Piedmontese expedition took place here, the Battle of Garigliano, fought on 29 October 1860, following which the Bourbon army took a final stand by barricading itself in Gaeta to defend the sovereign.