The Italian Campaign of World War II was the name of the Allied operations in and around Italy from 1943 until the end of the war. Following the victory in the North African Campaign, there was disagreement among the Allies over the next steps they should take.
The decision to invade Italy was made in January 1943 at the Casablanca Conference, the first war conference between the Allied Powers held in Casablanca, Morocco. The conference between Roosevelt and Churchill took steps towards planning the Allied strategy and the end of the war. It also established conditions for unconditional surrender.
Even as the Allies were preparing to invade Sicily, the Italian people and their government were still disillusioned with the war. Allied forces hoped that an invasion would pull Italy out of the war completely.
The elimination of Italy as an enemy would enable the Royal Navy to completely dominate the Mediterranean Sea, leading to vast improvements in communications with Egypt, the Far East, the Middle East and India. Capturing Italy would also provide airspace closer to Germany and the Balkans.