A journalist and politician, Mussolini had been a leading member of the National Directorate of the Italian Socialist Party (PSI) from 1910 to 1914, but was expelled from the PSI for advocating military intervention in World War I, in opposition to the party's stance on neutrality. Mussolini served in the Royal Italian Army during the war until he was wounded and discharged in 1917. Mussolini denounced the PSI, his views now centering on nationalism instead of socialism and later founded the fascist movement which came to oppose egalitarianism and class conflict, instead advocating "revolutionary nationalism" transcending class lines. Following the March on Rome in October 1922, Mussolini became the youngest Prime Minister in Italian history until the appointment of Matteo Renzi in February 2014. After removing all political opposition through his secret police and outlawing labor strikes, Mussolini and his followers consolidated their power through a series of laws that transformed the nation into a one-party dictatorship. Within five years, Mussolini had established dictatorial authority by both legal and extraordinary means and aspired to create a totalitarian state. In 1929, Mussolini signed the Lateran Treaty with the Vatican, ending decades of struggle between the Italian state and the Papacy, and recognized the independence of Vatican City.