Final answer:
The Fascists led by Benito Mussolini overthrew the Italian monarchy and established a Totalitarian state, with Mussolini being appointed prime minister in 1922 and becoming the dictator known as 'Il Duce'.
Step-by-step explanation:
The Fascists, under the leadership of Benito Mussolini, were responsible for overthrowing the king of Italy and establishing a Totalitarian state. In 1922, King Victor Emmanuel III appointed Mussolini as prime minister to thwart the threat of communism, following the highly symbolic 'March on Rome' by the Fascists.
Mussolini's government exerted state control over every aspect of social and economic life, instituting a system of state corporatism and declaring himself Il Duce, the supreme leader. His regime lasted until 1943 when he was deposed, although he was later reinstated by Adolf Hitler as a puppet ruler until his final oust just before the end of World War II in 1945.