This paper investigates the concept of aletheia in ancient philosophy from the pre-Socratics until Aristotle. The meaning of aletheia in archaic Greek is taken as the starting point. It is followed by remarks about the concept of truth in the Seven Sages. The author discusses this concept as it appears in views and works of philosophers and historians. A special section is devoted to the epistemological and ontological understanding of truth. On this occasion, influential views of Heidegger are examined. The (...) paper is concluded by a review of various meanings of truth in Aristotle. (shrink)