Plutarch, Life of TheseusCh. 32 ("But Dicaearchus says that Echedemus and Marathus of Arcadia were in the army of the Tyndaridae at that time, from the first of whom the present Academy was named Echedemia, and from the other, the township of Marathon, since in accordance with some oracle he voluntary gave himself to be sacrificed in front of the line of battle.")