Thucydides (c. 460 BC - 395 BC)
Greek historian, and the author of the History of the Peloponnesian War, which recounts the 5th century BC war between Sparta and Athens.
Thucydides is generally regarded as one of the first true historians. Like his predecessor Herodotus (often called "the father of history"), Thucydides placed a high-value on autopsy, or eye-witness testimony to events, and writes about many episodes in which he himself probably took part. He also assiduously consulted written documents and interviewed participants in the events that he records. Unlike Herodotus, he did not recognize divine interventions in human affairs. Certainly he held unconscious biases — for example, to modern eyes he seems to underestimate the importance of Persian intervention — but Thucydides was the first historian who attempted something like modern historical objectivity.