<P> Italy was an important member of the Axis powers in World War II, until it switched sides to the Allies in September 1943 after ousting Mussolini and shutting down the Fascist Party in areas (south of Rome) controlled by the Allied invaders . The remnant fascist state in northern Italy that continued fighting against the Allies was a puppet state of Germany, the Italian Social Republic, still led by Mussolini and his Fascist loyalists . Shortly after the war, civil discontent led to the constitutional referendum of 1946 on whether Italy would remain a monarchy or become a republic . Italians decided to abandon the monarchy and form the Italian Republic, the present - day Italian state . </P> <P> The Kingdom of Italy claimed all of the territory which covers present - day Italy and even more . The development of the Kingdom's territory progressed under Italian re-unification until 1870 . The state for a long period of time did not include Trieste or Trentino - Alto Adige / Südtirol, which are Italian territories today and only annexed them in 1919 . The Triple Entente promised to grant to Italy--if the state joined the Allies in World War I--several territories including former Austrian Littoral, western parts of former Duchy of Carniola, Northern Dalmazia and notably Zara, Sebenico and most of the Dalmatian islands (except Krk and Rab), according to the secret London Pact of 1915 . </P> <P> After the compromise was nullified under pressure of President Woodrow Wilson with the Treaty of Versailles, Italian claims on Northern Dalmazia were voided . During World War II, the Kingdom gained additional territory: it gained Corsica, Nizza and Savoia from France after its surrender in 1940, territory in Slovenia and Dalmazia from Yugoslavia after its breakup in 1941 and Monaco in 1942 . After World War II, the borders of present - day Italy were founded and the Kingdom abandoned its land claims . </P> <P> The Italian Empire also gained territory until the end of World War II through colonies, protectorates, military occupations and puppet states . These included Eritrea, Italian Somaliland, Libya, Ethiopia (occupied by Italy from 1936 to 1941), Albania, British Somaliland, Greece (occupied in World War II), Tunisia, Croatia (Italian and German client state in World War II), Kosovo (occupied in World War II), Montenegro (occupied in World War II) and a 46 - hectare concession from China in Tientsin (see Italian concession in Tianjin). </P>

How did germany respond to italys decision to switch sides in september 1943