Complex sentence: Previous bosses of the Sicilian Mafia were based in Palermo and kept violence to a minimum, they controlled large numbers of votes and had mutually beneficial relationships with local political figures such as Salvatore Lima.
Split into simpler sentences: Previous bosses of the Sicilian Mafia were based in Palermo and kept violence to a minimum. Their control of large numbers of votes enabled mutually beneficial relationships with local political figures such as Salvatore Lima.