The Italian mafia or mob was in Chicago before Capone arrived, or became boss there.
Maybe,but just because they were Sicilians you cannot consider them as the Mafia because they were not organized and also they were weaker than the Camorra.Back in the days the underworld in Chicago was divided in many different independent criminal groups or gangs of Italian immigrants.They were mostly involved in extortion and murder(and maybe in prostitution).Part of the Sicilian criminal population was involved in black hand activities and part was involved in the Unione Siciliani.The Unione Sicilani was not a criminal organization but it was,sort of controlled by them.The political bosses were mostly killing each other for the top spot.The first big Sicilian political boss was MIke Merlo and the first big independent Sicilian gangs were the Aiello's and the brutal Gennas.The point these gangs were not allies.For example,the Gennas were good killers alright but they were very bad for business.MOst of these gangs were very greedy and could not be organized.During prohibition some of them were exterminated and some of em joined forces with the Camorra and then became organized criminals.THe Aiello's were the last Sicilian "crime family" in Chicago.
After Merlo's death the Camorra or the Torrio/Capone gang took over in Chicago and held its power until the late 40's.Accardo was the first Sicilian boss of Chicagos underworld after 2 decades.But then again he always took advice or orders from an older camorrista,Paul Ricca.Same goes for Giancana...
