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 .
There historian began to write an account of the rise of Rome to a world power .
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 , and there he began to write an account of the rise of Rome to a world power .