Polybius was a Greek historian who lived in the 2nd century BCE. He is known for his comprehensive and detailed account of the Roman Republic, including the Punic Wars. His "Histories" is considered a primary source for information about the Battle of Cannae.
Polybius was present at the Battle of Pydna in 168 BCE, which marked the end of the Macedonian War. He was captured by the Romans and taken to Rome, where he had access to Roman archives and was able to interview participants in the Punic Wars. This allowed him to gather firsthand accounts and information about the battles, including Cannae.
Polybius's account of Cannae is particularly valuable because he describes the battle tactics and strategies of both sides in detail, as well as the political and social context surrounding the battle. He provides a balanced and insightful analysis of the events, highlighting the brilliance of Hannibal's military strategy and the devastating impact of the Roman defeat.