(Ἀριστείδης Κοϊντιλιανός), the author of a treatise in three books on music (Περὶ Μουσικῆς). Nothing is known of his history, nor is he mentioned by any ancient writer. But he must have lived after Cicero, whom he quotes (p. 70), and before Martianus Capella, who has made use of this treatise in his work De Nuptiis Philologiae et Mercurii, lib. 9. It seems probable also that he must be placed before Ptolemy, since he does not mention the difference between that writer and his predecessors with respect to the number of the modes. (Aristoxenus reckoned 13, his followers 15, but Ptolemy only 7. See Aristeid. pp. 22, 23; Ptol. Harm. 2.9.)
[W.F.D]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