One of the things that made the Roman Republic endure, both in reality and in the imagination, was its balance. According to the Greek historian Polybius, the three kinds of government, monarchy, aristocracy, and democracy, were all found united in Rome. And it was no easy thing to determine with assurance whether the entire state was an aristocracy, a democracy, or a monarchy. At the heart of this blended system was the Senate, a body of legislators chosen from a group of elite families. Rome was divided into two broad classes, the patricians, a small group of aristocratic families, and the plebeians, basically everyone else. The Senate was sort of a mixture of legislature and giant advisory council. Their main job was to set policy for the consuls.