"Thucydides [between 460 and 455 BC–circa 400 BC] is generally regarded as one of the first true historians. Unlike his predecessor Herodotus (often called "the father of history") who included rumors and references to myths and the gods in his writing, Thucydides assiduously consulted written documents and interviewed participants in the events that he records. By his discovery of historic causation...he created the first scientific approach to history...." (from Wikipedia.com)

"...Materials for his biography are scanty, and the facts are of interest chiefly as aids to the appreciation of his life's labour, the History of the Peloponnesian War....Thucydides' father Olorus, a citizen of Athens, belonged to a family which derived wealth and influence from the possession of goldmines at Scapte Hyle, on the Thracian coast opposite Thasos...Thus the fortune of birth secured three signal advantages to the future historian: he was rich; he had two homes-one at Athens, the other in Thrace-no small aid to a comprehensive study of the conditions under which the Peloponnesian War was waged; and his family connexions were likely to bring him from his early years into personal intercourse with the men who were shaping the history of his time." (from Internet Ancient History Sourcebook, part of the Internet History Sourcebooks Project at Fordham University)