I'm not sure if it was when the french occupied Sicily but I do know that the Mafia was created when Sicily was being occupied by foreigners and they tried to take it over, the Mafia was created to kick the foreigners out and to stop the killing of the Sicilian people. No one knows who came up with the idea, but we do know that a group of peasants came up with it and created it. But take into account that was the Sicilian Mafia (Cosa Nostra), there are other Mafias in Naples (Camorra) and Calabria ('Ndrangheta). The earliest records of the Mafia originated in Sicily so it could've spread into the other areas of Italy.