Polybius

Polybius a Greek historian and statesman (c. 200–118 BC) who wrote the Histories, a forty-book account of the rise of Rome to world power. His aim was to explain how and why the Romans conquered the Mediterranean world within fifty-three years, and in doing so he developed one of the most sophisticated theories of historical causation and of political cycles in antiquity.

Life and Political Career

Polybius was born into a prominent family of Megalopolis in the Achaean League, a federal state of Greek cities. He received a thorough education in politics and military affairs and rose to high office, serving as a cavalry commander and as a diplomat. These experiences gave him a practical understanding of political institutions and of the conduct of war.

After the Roman victory over Macedon in 168 BC, a thousand Achaean nobles were taken to Rome as hostages, among them Polybius. He spent some seventeen years in Italy, where he became a friend and adviser of Scipio Aemilianus, the son of the conqueror of Macedon. This connection gave him access to the highest circles of Roman politics and to firsthand information about Roman institutions.

He accompanied Scipio on campaigns in Africa and Spain and was present at the destruction of Carthage in 146 BC. In his later years he travelled widely, visiting the Alps and touring the western Mediterranean. He came to see his task as that of explaining Rome to the Greeks and of recording for posterity the most important political transformation of his age.

The Histories and Historical Method

The Histories were designed to cover the period from 220 to 146 BC, the years in which Rome completed its conquest of the Mediterranean, with an introductory survey of earlier events. Of the forty books, only the first five survive in full; the remainder are known from excerpts and fragments. The work is a unified account, bound together by the theme of Roman expansion.

Polybius insisted on the importance of accurate research and of firsthand testimony. He criticised historians who wrote from hearsay or in order to flatter, and he argued that the historian must have practical experience of politics and war if he is to understand the events he describes. He questioned eyewitnesses, studied documents and visited the sites of the battles he recorded.

He distinguished three modes of history: the genealogical, which pleases the ear, the pragmatic, which teaches by explaining causes, and the entertaining, which aims at display. His own aim was pragmatic history, the investigation of how things came about and of the lessons they offer to statesmen. This conception of history as a source of political education shaped the later tradition of classical historiography.

The Theory of the Mixed Constitution

Polybius is best known for his analysis of the Roman constitution, which he regarded as the cause of Roman success. Drawing on Greek political theory, he argued that there are three simple forms of government, monarchy, aristocracy and democracy, each of which degenerates in turn into tyranny, oligarchy and mob rule. This cycle, the anacyclosis, explains the instability of the Greek city-states.

The remedy, he held, is a mixed constitution that combines the three elements and allows each to check the others. In Rome the consuls represented the monarchical element, the senate the aristocratic, and the popular assemblies the democratic. The competition among these parts produced a balance that gave Rome both stability at home and energy abroad, and it was this balance, Polybius believed, that explained Roman ascendancy.

The theory had an extraordinary afterlife. It was taken up by Cicero, by Machiavelli, and by the founders of the American constitution, who studied Polybius and applied his idea of checks and balances to the design of a federal republic. His analysis of the cycle of constitutions remains one of the most influential pieces of ancient political thought.

Causation, Fortune and Providence

Polybius was deeply concerned with the causes of events and distinguished beginning, cause and occasion. The true cause of an event, he argued, is the intention and the decision that produce it, not the pretext that precedes it. He praised Thucydides for seeking the real causes of the Peloponnesian War and sought to emulate him in explaining the coming of Rome.

He made much use of the concept of Fortune, or Tyche, sometimes presenting her as a capricious power and sometimes as a providential force. His deepest conviction was that Rome's rise was the result of human intelligence, discipline and institutions rather than chance, and that even Fortune had favoured a state that deserved her favour. The tension between fortune and rational causation runs through the Histories.

He also believed in the usefulness of history for practical life. The historian, he wrote, is the teacher of statesmen, and the study of the past is the best preparation for the command of the present. This didactic conception, combined with his insistence on accurate research, made him a model for later writers from Tacitus to Machiavelli and beyond.

Legacy as a Historian

Polybius is valued by modern historians for his accuracy, his breadth of view and his analytical power. He is a principal source for the history of the Hellenistic world and of the Roman conquest, and his account of the Roman army and constitution is indispensable. Where his testimony can be checked it is generally found reliable, though his judgments are sometimes coloured by his admiration for Rome and for Scipio.

His theory of the mixed constitution and of the cycle of governments became a permanent part of Western political thought. The idea that liberty depends on a balance of powers, and that unchecked power leads to degeneration, is one of the most influential legacies of the ancient world, and it derives much of its force from Polybius's analysis of Rome.

He has been called the first modern historian for his concern with causes, his critical use of sources and his attempt to write a universal history. Whether or not the label is just, his achievement stands: he explained the greatest political upheaval of his time by reference to institutions and human decisions rather than to fate or the will of the gods, and he did so with an insight that later ages have never ceased to draw upon.

See also

• Thucydides
• Roman Republic
• Mixed government
• Scipio Aemilianus