If this individual is correctly named, he is otherwise unknown, and undatable. But perhaps [DW] he is Plato's friend and contemporary Helikon of Kyzikos, mentioned in Plutarch, Dion 19, as the recipient of a talent of silver from Dionysius II of Syracuse (delta 1179) for having correctly predicted a solar eclipse (in 360). The thirteenth Letter attributed to Plato calls him (360C) a pupil of Eudoxus (epsilon 3429).
[1] For this designation cf. e.g. zeta 160 (Zoroaster), mu 801 (Meton).
[2] i.e. the influence of the constellations on human life. cf. zeta 159 (Zoroaster again), mu 143 (Manetho), pi 810 (Paulos).