In January 1943 at Casablanca, Roosevelt and Churchill decided to force Italy out of the war. A landing in Sicily in July 1 943 cleared the east-west route across the Mediterranean. The island was captured within a month, but the German troops escaped. It was obvious that Italy had exhausted her resources. She had lost her empire. Her navy had been immobilized in its bases and was vulnerable to air attack. She could not withstand invasion. Industrial production had fallen by thirty-five per cent, while currency in circulation had trebled. Fascism had become increasingly unpopular as the Duce's physical and intellectual powers declined. Mussolini was not overthrown by his enemies, however, but by his supporters. On 24 July the Fascist Grand Council voted to 'restore the constitution'. In effect it dismissed Mussolini and restored absolute powers to the king. Victor Emanuel, with a few army chiefs, had resolved that Italy should stop fighting and reverse her alliances. He deposed Mussolini and then overcautiously ordered his arrest and imprisonment. Marshal Badoglio was appointed head of the government. While assuring the Germans that he would remain faithful to the Axis, he opened secret negotiations with the Allies which ended with Italy's unconditional surrender on 3 September 1 943, made public on 8 September. The surrender caused great confusion in Italy. The Allied troops under General Eisenhower's command did not penetrate north oi Naples, and Germans who had been prepared for Italy to defect, immediately occupied northern and central Italy, including Rome. Without great difficulty they disarmed the Italian troops in Italy and in the other occupied territories. But the Italian fleet escaped and surrendered to the Allies. The King and Badoglio fled to Brindisi where they attempted to ingratiate themselves with the Allies. As they lacked power, however, the Allies regarded them as enemies and the occupied territories were placed under martial law. Two new factors changed the situation. First Mussolini was released by SS parachutists. With his remaining supporters, he formed a Fascist republic at Salo in the north. He executed his son-in-law Ciano for having deserted him on 24 July. Second, anti- fascism surfaced throughout Italy. Exiles returning to Italy formed a new clandestine resistance movement, which fought both the Germans and the fascists. But they also fought the King and Badoglio, whom the Allies had accepted into their camp so as to keep a rein on them. Civil war ensued. In the liberated zone Badoglio quelled it by rallying the communists and admitting the leaders of the resistance into the Bonomi government; but in the sectors occupied by the Germans a full-scale war raged. A battle for position was fought from the south, northwards along the peninsula. The terrain was compartmentalized by mountains. It favoured defensive operations and cancelled out the Allied superiority in tanks and planes. The region around Monte Cassino witnessed particularly bitter fighting. The Allies, including a French expeditionary force under Juin, landed at Anzio in January 1944. They did not reach Rome until 4june, or Ravenna until December. The Italian surrender opened the way for Corsica to be liberated. In September 1943, French assault batallions were landed. They took the island in a combined operation with resistance fighters.