In the 1910s emerging Italian gangs were planning to take over the rackets of New York City. You had the Morrello Family Mafia in East Harlem and the Camorra Gangs in Brooklyn. Ironically the two factions would starts as allies in ridding the New York Underworld of its biggest players.
After assassinating the competition the Morello's did not settle who would over the rackets in Manhattan. This lead to war with the heads of each gang plotting to kill the other. Eventually the Camorra would gain the up[per hand.
It would be short lived as a Camorra snitch would bring the bloody war to an end.