Giuseppe Genco Russo was an Italian mafioso who was the boss of Mussomeli in the province of Caltanissetta, Sicily. Genco Russo, also known as "Zi Peppi Jencu", was an uncouth, sly, semi-literate thug with excellent political connections. A vulgar man, as he used to spit on the floor no matter who was present, he was often photographed with bishops, bankers, civil servants and politicians. He was considered to be the arbiter of Mafia politics, and was regarded as the successor of Calogero Vizzini, who had died in 1954. Although by then a wealthy landowner and politician as a member of Christian Democracy (DC), Genco Russo still kept his mule in the house and the toilet outside, which was little more than a hole in the ground with a stone for a seat and no walls or door according to Mafia turncoat Tommaso Buscetta.

Calogero "Don Calò" Vizzini was a Sicilian Mafia boss of Villalba in the province of Caltanissetta, Sicily. He was considered to be one of the most influential and legendary Mafia bosses of Sicily after World War II until his death in 1954. In the media, he was often depicted as the "boss of bosses" – although such a position does not exist in the loose structure of Cosa Nostra.