In 1922, he took power by having a large group of men, "Black Shirts," march on Rome and threaten to take over the government. King Vittorio Emanuele III gave in, allowed him to form a government, and made him prime minister. In the following five years, he gained power, and in 1927 created the OVRA, his personal secret police force. Using the agency to arrest, scare, or murder people against his regime, Mussolini was dictator of Italy by the end of 1927. Only the King and his own Fascist party could challenge his power.