How did Polybius use eyewitness testimony in writing history?

For the Greek historian Polybius, the questioning of witnesses and the use of oral sources were the most vital components of a historian’s work. He believed that relying on anything other than direct investigation resulted in "hearsay at one remove," which he considered an unreliable foundation for historical judgment.1

Polybius actively practiced this methodology by prioritizing personal experience and the cross-examination of eyewitnesses. His approach included:2

• Direct Observation: He traveled widely to gain firsthand knowledge of geographical features and military events, such as retracing Hannibal’s route across the Alps and observing the siege of Carthage in 146 BCE.123
• Rigorous Inquiry: He scorned historians who merely sat in their studies, arguing instead that a historian must possess political and military experience and actively engage with those who witnessed events.12
• Verification: By cross-examining participants and consulting primary sources—such as private letters, inscriptions, and official records—he sought to record "what really happened" rather than relying on the sensationalism or speculation common among his predecessors.14