 Polybius, a historian from the Greek city of Megalopolis in Arcadia, was taken as a hostage to Rome after the Roman defeat of the Achaean League in Achaean War, and there he began to write an account of the rise of Rome to a world power.The leading expert on Polybius' work was F. W. Walbank, who published a long commentary of Polybius, as well as a biography and several studies related to him.Polybius' "Histories" begin in the year 264 BC and end in 146 BC (Polybius was born around 200 BC and died around 117 BC).