On 25 July 1943, the Italians deposed their Fascist leader, Benito Mussolini. His successor, Marshal Pietro Badoglio, decided to make peace with the Allies and signed an armistice on 3 September. Italy's surrender was unconditional.
Although the Italians were the first Axis power to pull out of the war, their surrender did not appreciably alter the military situation. Disciplined and well-trained German defenders replaced Italian troops and dug in along well-fortified lines throughout southern Italy. The Allies' campaign against the entrenched Wehrmacht was not going to be easy.
The invasion of the Italian peninsula began on 3 September when Allied troops crossed the Straits of Messina, which separate Sicily from the Italian mainland. While the 8th US Army fought through Calabria (the "toe" of Italy's boot), other American forces landed at Salerno, south of Naples, six days later. The Canadians landed near Reggio Calabria and encountered very little opposition. Indeed, the initial phase of the peninsular campaign went very well for the Allies. By 20 September, the 1st Canadian Division had taken Potenza, a town 50 miles east of Salerno. On 1 October, the Allies liberated Naples. Canadian forces, which had been dispersed along the Adriatic coast, then reunited at Campobasso.
At the same time, Canada had decided to increase its commitment to the Mediterranean theatre. With the addition of the 5th Canadian Armoured Division, Canada now had a full army corps in the theatre. The buildup and equipping of these reinforcements of 1st Canadian Corps, which included the 5th Division and the 8,000 troops of the corps' support units, continued throughout the battles for Ortona.