A constitutional referendum was held in Italy on 2 June 1946, a key event of Italian contemporary history. Until 1946, Italy was a kingdom ruled by the House of Savoy, kings of Italy since the Risorgimento and previously rulers of Savoy. However, Benito Mussolini, enjoying the support of the reigning monarch, imposed fascism after the 28 October 1922 March on Rome, eventually engaging Italy in World War II alongside Nazi Germany. In 1946, Italy became a republic after the results of a popular referendum. Monarchists had suspicions of fraud, but were never allowed to prove these. A Constituent Assembly was elected at the same time.