The Greek historian Polybius, writing in the mid-2nd century BCE, emphasized (in Book 6) the role played by the Roman Republic as an institutional form in the dramatic rise of Rome's hegemony over the Mediterranean. In his writing on the constitution of the Roman Republic, Polybius described the system as being a "mixed" form of government. Specifically, Polybius described the Roman system as a mixture of monarchy, aristocracy, and democracy with the Roman Republic constituted in such a manner that it applied the strengths of each system to offset the weaknesses of the others. In his view, the mixed system of the Roman Republic provided the Romans with a much greater level of domestic tranquility than would have been experienced under another form of government. Furthermore, Polybius argued, the comparative level of domestic tranquility the Romans enjoyed allowed them to conquer the Mediterranean. Polybius exerted a great influence on Cicero as he wrote his politico-philosophical works in the 1st century BCE. In one of these works, "De re publica", Cicero linked the Roman concept of "res publica" to the Greek "politeia".