200 BC-Polybius and The Histories

Polybius (/pəˈlɪbiəs/; Greek: Πολύβιος, Polýbios; c. 200 – c. 118 BC) was a Greek historian of the Hellenistic period noted for his work, The Histories, 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 important for his analysis of the mixed constitution or the separation of powers in government, which was influential on Montesquieu's The Spirit of the Laws and the framers of the United States Constitution.

https://en.wikipedia.org/wiki/Polybius

Polybius’ Histories (Greek: Ἱστορίαι Historíai) were originally written in 40 volumes, only the first five of which are extant in their entirety. The bulk of the work is passed down to us through collections of excerpts kept in libraries in Byzantium. 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.

https://en.wikipedia.org/wiki/The_Histories_(Polybius)

http://www.perseus.tufts.edu/hopper/text?doc=Plb.+toc&redirect=true