(Ἡλιοκλῆς), a king of Bactria, or of the Indo-Bactrian provinces south of the Paropamisus, known only from his coins. Many of these are bilingual, having Greek inscriptions on the one side, and Arian characters on the reverse : whence it is inferred that he must have flourished in the interval between the death of Eucratides and the destruction of the Greek kingdom of Bactria, B. C. 127. It appears probable also, from one of his coins, that he must have reigned at one time conjointly with, or subordinate to Eucratides : and lassen, Mionnet, and Wilson, conceive him to be the son of Eucratides, who is mentioned by Justin as being at first associated with his father in the sovereign power, and who afterwards put him to death. (Just. 41.6; Lasen, Gesch. der Bactr. Könige ; Wilson's Ariana, p. 262.)
[E.H.B]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