Kingdom of Italy (1861–1946)
The Kingdom of Italy (Italian: Regno d'Italia) was a state forged in 1861 by the unification of Italy under the influence of the Kingdom of Sardinia; it existed until 1946 when the Italians opted for a republican constitution. The Kingdom was the first Italian state to include the entire Italian Peninsula since the fall of the Roman Empire.
During the time of the regime of the National Fascist Party under Benito Mussolini from 1922 to his ousting in 1943, the kingdom was often called by nationalists and Fascists as the Italian Empire (Italian: Impero Italiano) or the New Roman Empire (Italian: Nuovo Impero Romano, (Latin: Novum Imperium Romanum) but these were not used officially. Under fascism, the Kingdom allied with National Socialist Germany in World War II until 1943. In the remaining two years of World War II, the Kingdom of Italy switched sides to the Allies after the invasion on the Italian mainland, while Mussolini and the Italian Social Republic stayed with Germany until the end of war. Shortly after the war, civil discontent led to a referendum in 1946 on whether Italy would remain a monarchy or become a republic. Italians decided to abandon the monarchy and form the Italian Republic which is the present form of Italy today.