Joe Masseria
Pre-1931, "capo dei capi" (boss of bosses) was a term applied by mobsters to Giuseppe Morello around 1900, according to Nick Gentile. Bosses Joe Masseria (1928–1931) and Salvatore Maranzano (1931) used the title as part of their efforts to centralize control of the Mafia under themselves. When Maranzano won the Castellammarese War, he set himself up as boss of all bosses, created the Five Families, and ordered every Mafia family to pay him tribute. This provoked a rebellious reaction which led to him being murdered in September 1931, on the orders of Lucky Luciano.