Salvatore Maranzano (1868-1931) was an early Mafia boss in the United States. He was the only "Boss of Bosses" to control all Mafia activity. He came from the coastal town of Castellammare del Golfo, west of Palermo, Sicily.

Maranzano had a very commanding presence, and was greatly respected by his underworld peers. He had a fascination with Julius Caesar and the Roman Empire. He was a very formal man with Old World manners. Maranzano even studied to be a priest, and could possibly be the only Mafia boss in America to be college educated.

At the age of forty-three, Maranzano became the leader of the Castellammarese immmigrants in New York. Maranzano was sent to the U.S by Don Vito Cascio Ferro, where he met and allied with several other men sent by Don Ferro, including Joseph Bonanno, Joseph Profaci, and Stefano Magaddino. Maranzano's orders were to organize the American Mafia and bring it under Don Vito's control.

Maranzano's first move was to gain the support of the local Castellammare people. He then began to invade the territory of Joe "The Boss" Masseria. Maranzano hijacked truckloads of Masseria's liquor and taking over Masseria's bars. This started the Castellammarse War. The war lasted until Maranzano had Masseria killed, it is rumoured, by Lucky Luciano.

After the war, Maranzano began to organize the Mafia and implement rules, such as establishing five lieutenants, who would establish the Five Families which later ruled New York. Maranzano remained at the throne of the underworld only six months. He attempted to have his 5 top lieutenants assassinated, but Lucky Luciano and Vito Genovese others had him assassinated.

Following Maranzano's death, the lieutenants organized the Five Families and abolished the position of "tutto di tutti capi." Many of the old-order mafiosi in the United States were killed.