This paper studies the Archeology in the I book of Thucydides’ History (I 2-19) to highlight the close relationship between his approach to the study of ancient traditions and that of his successors, notably Ephorus. Writing contemporary history does not exclude the possibility of studying the past: it is impossible to have a complete and clear picture of what happened in ancient times, but we need to read data with critical tools. We can’t deal with the past as if it were present, but we can study traditional tales, usually accepted in their normal patterns, to find in them what interests us: Peloponnesian war is the largest of all previous, and we can understand it by reading the past. Thucydides shows a strong awareness of the presence of an audience that can no longer see what happened, but that can be deceived by the words of poets and logographers: he crosses the tradition with his logos, reporting what readers can still see. The past can be investigated, even if the data found will not be clear and bright. The Ephorus’ historical method in reading ancient history from the return of Heracleidae to the IV Century B.C. is based on these critical assumptions as we can understand from the surviving fragments of his work. In FGrHist 70 F 9 Ephorus is more a direct heir of Thucydides than an isocratean pupil. Keywords: Thucydides, Archeology, Ephorus, Greek Historiography, Universal history, Fourth-century Greek Historiography, Isocrates.