a celebrated Greek historian, was the son of Lycortas, a native of Megalopolis, in Arcadia, who succeeded Philopoemen in the chief direction of the Achaean league. His father, therefore, must have been one of the most distinguished men of his time; and we find him accordingly taking part in the principal transactions of his country. The exact date of his birth is unknown, but it is generally believed that it took place between B.C. 210–200; and his death was, therefore, not earlier than B.C. 129, as he lived to the advanced age of eighty-two. Plutarch tells us that the character of Polybius was formed under the eye of Philopoemen; and that at the funeral of that general he carried the urn which contained his ashes, B.C. 182. The following year he was, along with his father and the son of the celebrated Aratus, appointed as ambassador, to return thanks to Ptolemy Epiphanes for the assistance which he had offered to the Achaeans; but the death of that prince took place before the ambassadors left the Peloponnesus. In the war which arose between the Romans and Perseus king of Macedonia, the opinion of Polybius and his father Lycortas was, that the Achaeans should observe a strict neutrality; but they were overruled, and the Achaeans were implicated in the ruin of Perseus. To break the spirit of the Achaeans, and to prevent any further attempts at insurrection, more than a thousand of the principal citizens were sent to Rome, and afterwards dispersed throughout the different cities of Italy. Polybius was one of these exiles; but he was so far favoured that he was allowed to remain in Rome, where he resided for sixteen years, from B.C. 167 to 151. He became the intimate friend and instructor of Scipio the younger, Polybius, at that time only eighteen years old, and who afterwards showed how much benefit he had derived from the care Polybius bestowed on his education. At last, through the influence of Scipio and Cato, the senate was prevailed on to allow the Achaean exiles to return to their country; but of the original thousand only three hundred survived to enjoy the permission thus granted to them. Polybius seems now to have employed his time chiefly in travelling, with the view of acquiring more accurate notions of geography. He examined with great care and minuteness the passes of the Alps, that he might be enabled to give a correct account of the passage of Hannibal. He afterwards visited Gaul, Spain, and Africa, to which latter country he accompanied Scipio, B.C. 146, when that general took and destroyed Carthage. But the calamities of his own unhappy country called him away, and he hurried to the Peloponnesus, where his presence, however, was unable to save Corinth from the fate which had overtaken Carthage. He did all in his power to prevail on his countrymen to submit to a fate which they only made worse by resistance; and the Roman deputies felt such reliance on his good intentions, that they appointed him to the office of judge in all disputes that might arise in any part of the Peloponnesus. He gradually acquired the esteem of his countrymen, and many of the cities of Greece erected statues to his honour. He subsequently extended his travels into Egypt, which he visited in the reign of Ptolemy Physcon. Whether he was present with Scipio at the siege of Numantia, B.C. 134, we are nowhere told; but he left behind him a work on the subject. He also wrote a biographical sketch of Philopoemen, a work on Military Tactics, and another on the Equatorial Regions.

His principal work, however, was entitled General History, though it referred more particularly to a space of fifty-three years (from 220 to 168 B.C.), from the commencement of the second Punic war, where the historian Timaeus, and Aratus of Sicyon, had stopped, to the defeat of Perseus, king of Macedonia, by the Romans. It was divided into forty books, of which we now only possess the first five entire, and rather long fragments of most of the others. The first two books are occupied with introductory matter, giving a sketch of the events that happened anterior to the second Punic war. He explains the causes which gave rise to the first Punic war, and then relates the various events which took place during the twenty-four years it lasted. He gives also some account of the contest which arose between the Carthaginians and their stipendiaries. The second book contains the wars of the Eoceans, Illyrians, Achaeans, the expeditions of the Romans against the Illyrians and Gauls, and the transactions of Antigonus king of Macedonia, and Cleomenes king of Sparta, occupying a period of seventeen years, from B.C. 237 to 220. The third book enters into what is more properly the subject of his history, and, after explaining what he considers to be the true causes of the second Punic war, follows the path of Hannibal's victories as far as the battle of Cannae, B.C. 216. Yet it would appear that he was defective in method, as the fourth book carries us back to anterior events, which had happened in 220, 219, 218, B.C. After a sketch of the people of the East during the reign of Philip, son of Demetrius king of Macedonia, of Ariarathes king of Cappadocia, of Antiochus king of Syria, and Ptolemy Philopator king of Egypt, this book traces the history of wars and seditions in Greece. In the fifth book we have the victories of Philip, the wars in Syria between Antiochus and Ptolemy, and the confederated arms of Greece turned against Rome. It would be useless to give any detailed account of the fragments of the thirty-five books that have been preserved; but we know that the thirty-ninth book ended with the destruction of Corinth, B.C. 146. Polycarp. There have been many editions of this work, but the most critical is that of J. Schweighäuser, eight vols. Svo, Leipzig, 1789-1795. It has been translated into English by Hampton; into French by Folard, six vols. Par. 1727, with numerous plates and critical annotations; into German by Chr. Seybold, Lemgo; 1789-1783, and by L. Storch, Prenzl., 1828. See Polybi et Appiani Historiarum Excerpta Vatilana recognita a J. F. Lucht, Altona, 1830.