During World War II, the Armistice of Cassibile was signed on September 3, 1943, and made public on September 8, 1943, between the Kingdom of Italy and the Allies. At a meeting of generals from both sides in an Allied military camp at Cassibile, Sicily, which the Allies had recently invaded, it was signed by Brigade General Giuseppe Castellano for Italy and Major General Walter Bedell Smith for the Allies. The armistice was signed by both King Victor Emmanuel III of Italy and Marshal Badoglio, Italy's prime minister. Germany moved quickly by releasing Benito Mussolini (12 September) and attacking Italian forces in Italy (8–19 September), southern France, and the Balkans. The Italian troops were rapidly destroyed, and German soldiers conquered most of Italy, establishing the Italian Social Republic as a puppet state. Most of the navy and the Italian government fled to Allied-controlled territory.
Following the Axis powers' surrender in North Africa on May 13, 1943, the Allies bombarded Rome on May 16, invaded Sicily on July 10, and prepared to land on the Italian mainland on August 10. The Italian dictator, Benito Mussolini, removed several officials from the cabinet in the spring of 1943, preoccupied with the dismal state of the Italian military during the war. He believed they were more loyal to King Victor Emmanuel III than the Fascist dictatorship. To aid him in carrying out his plan, the King enlisted the support of Dino Grandi (1st Count of Mordano), a vital member of the Fascist hierarchy who, in his younger years, was considered the only realistic alternative to Mussolini as leader of the National Fascist Party. The King was also motivated by the fear that the Count of Mordano's views on Fascism would be quickly modified. As a result, various ambassadors, including Pietro Badoglio, floated the idea of him succeeding Mussolini as dictator to him.
Giuseppe Bottai, a high-ranking member of the Fascist Directorate and Minister of Culture, and Galeazzo Ciano (the 2nd Count of Cortellazzo and Buccari), the Fascist Party's second-most powerful man and Mussolini's son-in-law, were among the secret rebels afterwards. The conspirators created an "Order of the Day" for the next meeting of the Grand Council of Fascism (Gran Consiglio del Fascismo), which confined a proposal to restore direct political control to the King. A majority vote adopted the "order of the day" following the Council on July 25, 1943, and Mussolini was summoned to face the King and ousted as Prime Minister. Mussolini was apprehended by carabinieri after leaving the conference and taken to the island of Ponza. Although Mordano had been assured that another general with more substantial personal and professional qualifications (Marshal Enrico Caviglia) would have received the role, Badoglio became President of the Council of Ministers (Prime Minister).
The appointment of Badoglio appears to have had no impact on Italy's status as a wartime ally of Germany. On the other hand, many channels advocated for a peace pact with the Allies. Meanwhile, Hitler dispatched many divisions south of the Alps, ostensibly to assist in defence of Italy against Allied landings but evidently to take control of the country.
Three Italian generals were sent to Lisbon independently to contact Allied diplomats, including Brigade General Giuseppe Castellano. First, the Allies needed to identify the most authoritative ambassador; the three generals had begun to feud over who had the most power. Finally, Castellano was permitted to talk with the Allies about the terms of Italy's capitulation. Among the Allies' representatives were the British Ambassador to Portugal, Sir Ronald Hugh Campbell, and two generals dispatched by Dwight Eisenhower: the British Kenneth Strong (assistant chief of staff for intelligence) and the American Walter Bedell Smith (Eisenhower's chief of staff). General Castellano returned to Italy on August 27 and briefed Badoglio three days later on the Allied proposal for a summit in Sicily, as indicated by the British Ambassador to the Vatican. Dick Mallaby, a captured British Special Operations Executive (SOE) agent, was released from Verona Prison and secretly relocated to the Quirinale to facilitate contact between the Allies and the Italian government. The Germans needed to be kept in the dark about any indication of Italian capitulation, and the SOE was deemed as the safest way under the circumstances.
Badoglio still believed that favourable terms might be obtained in exchange for the surrender. He told Castellano that any surrender of Italy must be contingent on Allied soldiers landing on the Italian mainland. The Allies held only Sicily and a few other islands at the time. Brigade General Castellano arrived in Sicily by plane on August 31st and was transported to Cassibile, a town near Syracuse. Early on, it was clear that the two sides in the negotiations had taken stances that were somewhat dissimilar. After the signing, Castellano lobbied for the Italian territory to be protected from the expected reaction of the German Wehrmacht against Italy. He was only given vague promises in exchange, such as forming a parachute section over Rome.
Furthermore, the steps were to occur concurrently with the signing, rather than before it, as the Italians had requested. Badoglio and his entourage greeted Castellano the following day. Raffaele Guariglia, Italy's Foreign Minister, indicated that the Allied demands would be approved. Other generals, like Giacomo Carboni, claimed that the Army Corps stationed around Rome was unable to protect the city due to a lack of fuel and ammunition and that the armistice had to be postponed. In the encounter, Badoglio did not make a formal introduction. Instead, he stood before the King in the afternoon, who agreed to the ceasefire terms.
The Allies received a confirmation message. However, the Wehrmacht intercepted the communication (German military forces), which had long suspected Italy was pursuing its armistice. The Germans called Badoglio, who reaffirmed Italy's unshakeable commitment to its German ally on several occasions. However, the Germans were sceptical of his pledges, so the Wehrmacht devised Operation Achse, a plot to seize control of Italy as soon as the Italian government pledged allegiance to the Allies. On the 2nd of September, Castellano returned to Cassibile with orders to confirm the Allied conditions' acceptance. However, he had no official authorization from the Italian government's leader, who wished to distance himself as much as possible from his country's impending defeat.
On September 3rd, at 14:00, the signing ceremony commenced. On behalf of Badoglio and General Eisenhower, Castellano and Bedell Smith signed the acceptable document. A 500-plane bombing mission on Rome was called off at the last minute, and Eisenhower used it as a deterrence to speed up the armistice process. Winston Churchill was notified by Harold Macmillan, the British government's representative minister at the Allied Staff, that the armistice had been contracted "without any alterations of any kind."
General Campbell had submitted new clauses to another Italian general, Zanussi, who had also been in Cassibile since August 31. Only after the signing was Castellano told of the additional provisions. Zanussi had not notified Castellano about them for unknown reasons. Nonetheless, Bedell Smith clarified to Castellano that the other criteria would only have taken effect if Italy had not joined the Allies in waging war.
Badoglio met with top commanders of the Regia Marina (Italy's Royal Navy), the Regia Aeronautica (Italy's Royal Air Force), the War Ministers, and the King's deputies in the afternoon of the same day. However, he did not acknowledge the signing of the ceasefire, instead referring to ongoing negotiations. The date on which the armistice went into effect was connected to a planned landing in central Italy and was left to the discretion of the Allies. Castellano was still under the impression that the date was September 12th, and Badoglio began moving troops to Rome.
On September 7, a small Allied team arrived in Rome to advise Badoglio that the armistice would be signed the next day. He was also notified of the American 82nd Airborne Division's impending arrival at airports throughout the city. Badoglio informed the delegation that his force was not prepared to support the landing and that Germany controlled most of the area's airports. Therefore, he requested that the truce be postponed for a few days. The landing of American troops in Rome was cancelled when General Eisenhower learnt of this, but the date of the armistice was confirmed since other troops were en route by sea to land in southern Italy.
When the armistice was declared by Allied radio on September 8, German forces launched Operation Achse against Italian forces. The ceasefire had gone unnoticed by the majority of the Regio Esercito (Italian Royal Army), and no clear directives had been provided regarding the course of behaviour to be taken in the face of the German armed forces. Some of the Italian troops supposed to protect Rome were still passing through southern France. On the morning of the 9th, the monarch, the royal family, and Badoglio escaped Rome, seeking refuge in Brindisi, in southern Italy. The plan had been to move army headquarters, together with the King and Prime Minister, out of Rome, but only a few staff officers made it to Brindisi.
Meanwhile, the Italian troops disintegrated without orders and were quickly defeated; some small units remained loyal to the German ally. Except for Sardinia and a portion of Apulia, German soldiers conquered all Italian territories that were still not under Allied control from September 8 to 12 without encountering much-organized resistance. In Rome, an Italian governor ostensibly administered the city until September 23 with the help of an Italian infantry division, but the town had been under German authority since September 11th. On September 3, British and Canadian forces crossed the Strait of Messina near Operation Baytown and began landing in Calabria's southernmost peninsula. The Allies landed at Salerno and Taranto the day after the armistice was made public, on September 9th.
The Allies failed to exploit the Italian armistice fully and were swiftly thwarted by German forces. The Allied troops acquired 20 months to reach Italy's northern frontiers in terrain favoured defence. In the occupied Balkans and Greek islands, some Italian troops stationed outside Italy could hold out for a few weeks after the armistice. Still, they were all sceptical by the Germans, without any determined backing from the Allies. After resisting German soldiers on the island of Cephalonia, the Italian Acqui Division was murdered. On the island of Kos, 103 Italian officers of the 50th Infantry Division Regina met a similar fate after the Germans conquered the island in early October 1943. Only with British reinforcements on the islands of Leros and Samos did resistance persist until November 1943, and in Corsica, Italian troops forced German troops to abandon the island. Individual Italian troops of varied sizes remained on the Axis side in other circumstances. Many of the regiments were the backbone of the Italian Social Republic's armed forces.
Both the Regia Aeronautica (Italian Royal Air Force) and the Regio Esercito (Italian Royal Army) was virtually dissolved with the proclamation of the armistice on September 8. The Allies wanted the Regia Marina (Italian Royal Navy), which had 206 ships, including Vittorio Veneto, Roma, and Italia (known as Littorio until July 1943). Some fleets were at risk of fighting, being scuttled, or (more critically for the Allies) falling into German hands. As a result of the truce, Italian warships on the west coast of Italy, mainly at La Spezia and Genoa, were ordered to sail to North Africa through Corsica and Sardinia. In contrast, those in the heel of Italy, Taranto, were called to sail to Malta. At 02:30 on September 9th, the three battleships Vittorio Veneto, Roma, and Italia "shoved off from La Spezia accompanied by three light cruisers and eight destroyers." Enraged by the ships' escape, German troops who had poured into town to prevent the defection "picked up and summarily murdered many Italian captains who, unable to get their warships underway, had scuttled them." That afternoon, German bombers launched guided bombs against ships sailing without air protection off the coast of Sardinia. Several vessels were damaged, and the Roma sank, killing roughly 1,400 men. Most of the remaining ships made it to North Africa safely, "while three destroyers and a cruiser moored in Menorca to rescue survivors." In other parts of Italy, the navy's transition went more smoothly. When an Allied naval force approached Taranto's large maritime station, it saw a flotilla of Italian ships sailing out of Taranto harbour on their way to Malta to surrender.
In late September, the Allies and the Italians reached a deal to keep portions of the fleet in service, but the battleships were restricted to care and maintenance and effectively disarmed. The general operating conditions for Italian mercantile marine vessels were the same as the Allies. The Italian ships would keep their Italian personnel and fly Italian flags in all situations.