The Siege of Ancona took place between 24 and 29 September 1860 during the Piedmontese campaign in central Italy. Following their defeat at the Battle of Castelfidardo, the remnants of the Papal States army under General Louis Juchault de Lamoricière retreated into the port city of Ancona. The city was blockaded by the Royal Sardinian Navy and surrounded on land by the Royal Sardinian Army commanded by General Manfredo Fanti. After a combined land and sea bombardment that resulted in the destruction of the Forte della Lanterna, the Papal garrison surrendered on 29 September. The capture of Ancona secured the Marche and Umbria regions for the Kingdom of Sardinia, facilitating the subsequent unification of northern and southern Italy.
Background
On 18 September 1860, the Papal field army was defeated by Sardinian forces at the Battle of Castelfidardo. Following the rout, General Lamoricière abandoned his main forces and fled toward the coast with a small escort of cavalry. While Sardinian troops attempted to intercept him near Numana, Lamoricière utilized coastal paths and arrived in Ancona on the evening of 18 September to take command of the city's defenses.
Ancona was a primary naval base and fortress in the Adriatic. Lamoricière intended to hold the city to await reinforcements and supplies from Catholic European powers via the sea.
Opposing forces
Sardinian forces
The Sardinian land forces surrounding Ancona numbered approximately 16,500 men under the overall command of General Manfredo Fanti. The naval blockade and bombardment were conducted by a squadron of the Royal Sardinian Navy commanded by Admiral Carlo Pellion di Persano. The fleet included the steam frigates Maria Adelaide (flagship), Vittorio Emanuele, and Carlo Alberto, the corvettes Costituzione and Governolo, and several other vessels. The Sardinian warships were equipped with Paixhans guns and rifled artillery capable of firing heavy explosive shells.
Papal forces
The Papal garrison consisted of between 4,100 (according to Papal records) and 6,000 men (according to Sardinian prisoner counts), including remnants of the field army and local defense units. The defenses were armed with 129 artillery pieces of various calibers, including mortars and 36-pounder guns. The harbor entrance was obstructed by wooden pilings, a heavy iron chain stretched between the piers, and armed floating pontoons.
Siege
Naval blockade and initial engagements
The Sardinian naval presence began on 16 September when the frigate Costituzione conducted a reconnaissance mission off the harbor. On 18 September, an exchange of artillery fire occurred between the Papal coastal forts and Persano's ships. By 24 September, Sardinian land forces had captured the Lunetta Scrima outwork, completing the encirclement of the city. Over the next two days, Sardinian troops engaged Papal outposts and secured the strategic heights of Monte Pulito and Monte Pelago.
During the siege, an assassination attempt was made on Lamoricière while he was inspecting the fortress parapets. A local Papal soldier was accused of firing the shot, but was subsequently cleared following an investigation and the testimony of General Hermann Kanzler.
Land and sea assaults
Sardinian forces advanced toward the Borgo Pio district and bombarded Porta Pia in an attempt to breach the city walls. Concurrently, the XVI Bersaglieri Battalion executed an amphibious assault using small boats, successfully capturing the Lazzaretto. Once the Lazzaretto fell into Sardinian hands, it was subjected to crossfire from the remaining Papal fortifications.
On 28 September, the Sardinian army launched a major infantry assault against Porta Farina and Porta Calamo, but the attack was repelled by the defenders. The decisive action occurred at sea. Admiral Persano concentrated the fire of his warships on the Forte della Lanterna, which guarded the harbor mouth. A Sardinian shell struck the fort's powder magazine, causing a massive explosion that destroyed the structure and killed approximately 125 Austrian artillerymen stationed inside.
Surrender
With the loss of the Lazzaretto and the Forte della Lanterna, the harbor was breached, and the city's sea defenses were neutralized. Recognizing that no foreign relief force would arrive in time, Lamoricière ordered the cessation of hostilities. The formal unconditional surrender was signed on 29 September 1860 at Villa Favorita, outside the city.
Aftermath
The fall of Ancona resulted in the capture of the remaining Papal forces in the region and the seizure of the fortress's artillery. The Sardinian victory secured the annexation of the Marche and Umbria, which was formalized through plebiscites in November 1860. This territorial expansion connected the northern domains of the House of Savoy with the southern territories recently conquered by Giuseppe Garibaldi.
On 3 October 1860, King Victor Emmanuel II arrived in Ancona aboard the Governolo. He was received by military salutes and entered the city, later departing to meet Garibaldi at Teano.
Defenses of Ancona in 1860
The city's defenses were divided into sea and land fortifications. The sea defenses included the Forte della Lanterna, the Lazzaretto, and batteries located on the Cappuccini and Cardeto hills, as well as the port walls. The land defenses were anchored by the Cittadella, the Campo Trincerato, the Lunetta Santo Stefano, and the Baluardo di San Paolo. The distribution of the 129 recorded artillery pieces was as follows: