(Ἀχιλλεύς), a son of Lyson of Athens, who was believed to have first introduced in his native city the mode of sending persons into exile by ostracism. (Ptolem. Heph. vi. p. 333.) Several other and more credible accounts, however, ascribe this institution with more probability to other persons.
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890