Rome is the largest city in Italy, but it is not the city most plagued by the Mafia; there are seven notable Mafia families, big and small.
The largest one is called the Parini Family, which holds sway over both the underworld and the legitimate world, owning a publicly traded company, with several members holding positions in the government of Rome. If it were not for their Mafia background, they would have at least one high-ranking official among them.
The smallest family controls only a bar and a hotel, though it has a long history of nearly a hundred years. Its existence is fragile, a today-there-tomorrow-gone sort of situation, with brawls even handled personally by family members. Calling it a family rather than a household would be more fitting.
However, the Mafia people truly value legacy, even if they end up as just a gangster family, they still carry a notable reputation.