The Castellammarese War (1929 - 1931) was a bloody power struggle for control of the Italian-American mafia between two factions. The war ended with Salvatore Maranzano, head of the Castellammarese faction, becoming capo di tutti capi (Boss of All Bosses) for the entire mafia. After he was killed, "the Commission" of five mafia families of equal stature was established.