On 23 September 1943, Benito Mussolini proclaimed the Italian Social Republic(ISR), the so-called Salò Republic, which was headquartered in the town of Salò in the extreme north of Italy. The new republic was a puppet regime and Mussolini had himself become little more than a puppet under the control of Adolf Hitler.

Germany took over Trieste, Istria, and other regions in northern Italy. The section of the Italian peninsula governed by the Salò Republic would gradually shrink as the American and British armies advanced from the south.

The ISR army continued to fight although recruitment proved increasingly difficult. The ISR had a small air force but the navy was almost non-existent. The bulk of the Italian fleet had already surrendered to the British.

The ISR existed throughout 1944. It finally collapsed on 25 April 1945 when Mussolini and his mistress, Clara Petacci, escaped and were on the run.