Polybius (; , Polýbios;  –  BC) was a Greek historian of the Hellenistic Period noted for his work, which covered the period of 264–146 BC in detail. The work describes the rise of the Roman Republic to the status of dominance in the ancient Mediterranean world and included his eyewitness account of the Sack of Carthage in 146 BC. Polybius is also renowned for his ideas concerning the separation of powers in government, later used in Montesquieu's The Spirit of the Laws and in the drafting of the United States Constitution.