(Εὔθυμος), a hero of Locri in Italy, was a son of Astycles or of the river-god Caecinus. He was famous for his strength and skill in boxing, and delivered the town of Temessa from the evil spirit Polites, to whom a fair maiden was sacrificed every year. Euthymus himself disappeared at an advanced age in the river Caecinus. (Strab. vi. p.255; Aelian, Ael. VH 8.18 ; Eustath. ad Hom. p. 1409.) He gained several victories at Olympia (Ol. 74, 76, and 77); and a statue of his at Olympia was the work of Pythagoras. (Paus. 6.6.2, 10.2.)
[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