Most of the people in business with him were Italian (except his business manager Jake Guzik). They weren't necessarily Sicilian, but Italian. The city of Chicago is, by nature, more diverse than New York was. Large sections of the city were controlled by non-Italians - especially the north side of the city where the Irish were in control. This is where the O'Bannion and later Moran gang were located. It is also the part of town that Hymie Weiss is from (real name Earl Wajciechowski).
A lot of the Chicago gangsters had different names. Machine Gun Jack McGurn, who worked for Capone, is really Vincert Gebardi.
"After all, we are not communists"
Christopher Moltisanti: You ever think what a coincidence it is that Lou Gehrig died of Lou Gehrig's disease?
Tony Soprano: Yeah well, when you're married, you'll understand the importance of fresh produce.
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