About the author
Greek historian (c. 200–118 BC), brought to Rome as a hostage, where he became an intimate of the Scipio family and an eyewitness to Rome's expansion. His Histories aimed to explain how Rome conquered the Mediterranean in fifty years; his analysis of the mixed constitution made him a foundational figure in the republican tradition.
Synopsis
In the famous sixth book of his history of Rome's rise to Mediterranean dominance, Polybius sets out the theory of anacyclosis — the natural cycle by which monarchy degenerates into tyranny, aristocracy into oligarchy, and democracy into mob rule — and argues that a 'mixed' constitution blending all three stable elements can arrest this decay. Rome's success, he contends, owed much to having achieved just such a balance.
Core passage idea
Paraphrase · Public domainPolybius argues that each simple form of government carries the seed of its own corruption, and that the most stable and powerful state is one that mixes monarchy, aristocracy, and democracy so that each checks the others.
The idea that mixing and balancing powers can resist the natural decay of any single form is the ancestor of constitutional checks and balances. Through Machiavelli, Montesquieu, and the Federalist, Polybius's analysis of the mixed constitution helped shape modern republican government.
To avoid a bubble
Pair with Aristotle's Politics, whose analysis of constitutions Polybius builds on, and with modern critics who question his cyclical theory of constitutional decay (anacyclosis) and his idealized portrait of the Roman balance.
Reading note
Read Book VI on the Roman constitution rather than the whole vast history. It is the crucial link between Aristotle's constitutional theory and the modern doctrine of separated, balanced powers.
Best paired with
Aristotle, Politics; The Federalist Papers.