Overview
In Greek mythology, Orthrus (, Orthros) or Orthus (, Orthos) was, according to the mythographer Apollodorus, a two-headed dog who guarded Geryon's cattle and was killed by Heracles. He was the offspring of the monsters Echidna and Typhon, and the brother of Cerberus, who was also a multi-headed guard dog.
Name
His name is given as either "Orthrus" (Ὄρθρος) or "Orthus" (Ὄρθος). For example, Hesiod, the oldest source, calls the hound "Orthus", while Apollodorus calls him "Orthrus".
Mythology
According to Hesiod, Orthrus was the father of the Sphinx and the Nemean Lion, though whom Hesiod meant as the mother, whether it is Orthrus' own mother Echidna, the Chimera, or Ceto, is unclear.
Orthrus and his master Eurytion were charged with guarding the three-headed, or three-bodied giant Geryon's herd of red cattle in the "sunset" land of Erytheia ("red one"), an island in the far west of the Mediterranean. Heracles killed Orthrus, and later slew Eurytion and Geryon before taking the red cattle to complete his tenth labor. According to Apollodorus, Heracles killed Orthrus with his club, although in art Orthrus is sometimes depicted pierced by arrows.
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