Polybius

Polybius was born about 200 BC at Megalopolis in Greece and was a statesman and cavalry commander of the Achaean League. After Rome conquered Macedon he was taken to Rome as one of a thousand hostages, yet there he became the friend and teacher of the general Scipio Aemilianus and witnessed the destruction of Carthage. He set out to explain how Rome had conquered almost the whole known world in just fifty-three years; his answer, the stability of a mixed constitution, deeply influenced Montesquieu and the framers of the American Constitution.