Hercules kills Geryon and his dog by Cornelis Cort, after Frans Floris  (ca. 1563–95)

Hercules (center) battles Geryon (right) and his two-headed dog Orthus (bottom). Hercules kills Geryon and his dog by Cornelis Cort, after Frans Floris (ca. 1563–95).

RijksmuseumPublic Domain


Orthus was a two-headed dog, one of the fearsome children of Echidna and Typhoeus. He served as a guard dog to Geryon, a monster with three heads and three bodies who lived somewhere at the edge of the world. When Heracles came to steal Geryon’s cattle for his tenth labor, both Orthus and his master were killed while trying to defend the herd.


The name “Orthus” (Greek Ὄρθος, translit. Órthos)[1] may be etymologically connected to the Greek noun ὄρθρος (órthros), meaning “daybreak, dawn”—a word that may itself have Indo-European origins.[2] The name also resembles another Greek word, ὀρθός (orthós), meaning “straight, upright.”


  • English
    Orthus, OrthrusὌρθος (translit. Órthos), Ὄρθρος (translit. Órthros)
  • Phonetic
    [OR-thus]/ˈɒr θəs/


Orthus lived with his master (and cousin) Geryon in “sea-girt” Erytheia,[3] a mysterious land at the edge of the world. Most ancient writers placed it somewhere in Spain, in the neighborhood of modern Cadiz.[4]

Orthus was typically said to have been a two-headed dog.[5] But in artistic depictions (mostly on vase paintings), the number of heads varied between one and three. Sometimes he was also shown with a snake in place of a tail.[6] In at least one tradition, Orthus was imagined as multiple guard dogs rather than a single multi-headed dog.[7]

One late source added that he had seven dragon or snake heads in addition to the canine ones.[8] 

Orthus appeared only sporadically in ancient art, and only in connection with Heracles’ tenth labor (the theft of Geryon’s cattle). In those scenes, Orthus was usually shown lying dead, often with arrows protruding from his body.[9]

Orthus attic red-figure kylix signed by Kachrylion and Euphronios circa 510-500 BCE

Hercules Kills Geryon and his Dog by Cornelis Cort (ca. 1563–1595).

RijksmuseumPublic Domain


Orthus was one of the terrifying children of the monsters Typhoeus and Echidna.[10] His siblings included Cerberus, the three-headed guard dog of the Underworld, who was captured by Heracles;[11] the Hydra, a many-headed serpent, who, like Orthus, was slain by Heracles;[12] and (possibly) the Chimera, a fire-breathing creature with the features of a goat, a lion, and a snake, who was killed by Bellerophon.[13]

Family Tree


Orthus’ only mythological role was in connection with Heracles’ famous Twelve Labors. For the tenth labor, Heracles had been commanded by Eursytheus, his taskmaster, to travel to Erytheia and bring back the splendid cattle of Geryon.

When Heracles reached Erytheia, he first had to face Geryon’s guard dog, Orthus, and his herdsman, Eurytion. But this did not detain him long. According to Apollodorus, Heracles killed Orthus with a single swing of his heavy club. When Geryon’s herdsman came to help, Heracles swiftly dispatched him, too. 

Geryon finally armed himself and came out to meet the hero who was hell-bent on stealing his cattle. But Heracles killed him just as quickly—either with his club or, according to Apollodorus, with a single arrow.[15]

Heracles killing Geryon relief panel from Villa Chiragon third century CE

Marble relief panel showing Heracles slaying Geryon. From the Villa Charigon (3rd century CE).

Musee Saint-Raymond, Toulouse, FrancePublic Domain



  1. The name is sometimes (though more rarely) spelled “Orthrus” (Greek Ὄρθρος, translit. Órthros). On the alternative forms of Orthus’ name, see Martin L. West, Hesiod: Theogony (Oxford: Clarendon, 1966), 248–49 (on l. 293).

  2. Cf. Robert S. P. Beekes, Etymological Dictionary of Greek (Leiden: Brill, 2009), 2:1101–2.

  3. Hesiod, Theogony 290, 983, trans. H. G. Evelyn-White.

  4. On the location of Erytheia, see esp. Stesichorus, Geryoneis frag. 184 Poetae Melici Graeci (PMG); Herodotus, Histories 4.8.2; Strabo, Geography 3.2.11, 3.5.4; Diodorus of Sicily, Library of History 4.18.2; Apollodorus, Library 2.5.10; Pliny the Elder, Natural History 4.22.120. Besides Cadiz, other locations suggested by ancient writers were Ambracia in Greece (Hecataeus of Miletus, Fragmente der griechischen Historiker (FGrH) 1 frag. 26) and Mauritania in northern Africa (Ptolemy, Geography 4.1.16).

  5. Apollodorus, Library 2.5.10; Servius on Virgil’s Aeneid 7.662.

  6. See Susan Woodford, “Orthros I,” in Lexicon Iconographicum Mythologiae Classicae (Zurich: Artemis, 1997), 7:105–7.

  7. Pindar, Isthmian Ode 1.13.

  8. John Tzetzes on Lycophron’s Alexandra 653.

  9. See Susan Woodford, “Orthros I,” in Lexicon Iconographicum Mythologiae Classicae (Zurich: Artemis, 1997), 7:105–7.

  10. Hesiod, Theogony 309; Apollodorus, Library 2.5.10.

  11. Hesiod, Theogony 310ff; cf. Sophocles, Trachinian Women 1097ff; Hyginus, Fabulaepreface, 151.

  12. Hesiod, Theogony 313ff; cf. Hyginus, Fabulaepreface, 151.

  13. esiod, Theogony 319ff. The passage is ambiguous, however, in describing the parentage of the Chimera; another possible interpretation is that the Chimera was the offspring not of Echidna but of the Hydra. Cf. Martin L. West, Hesiod: Theogony (Oxford: Clarendon, 1966), 254–55 (on l. 319). But see also Apollodorus, Library 2.3.1, where Typhoeus and Echidna are named as the parents of the Chimera.

  14. Hesiod, Theogony 326–27.

  15. Apollodorus, Library 2.5.10; cf. Hesiod, Theogony 287ff, 979ff; Stesichorus, Geryoneis frag. 181–86 Poetae Melici Graeci (PMG), frag. 7–86 Supplementum Lyricis Graecis (SLG); etc.

Primary Sources

The following is a selected list of important Greek and Roman sources on Orthus. Further sources and citations can be found in the notes above.


  • Hesiod (eighth/seventh century BCE): Orthus’ genealogy and mythology are summarized in the Theogony (287ff, 979ff).

  • Stesichorus (mid/late seventh century–ca. 550 BCE): Stesichorus’ Geryoneis, a long lyric poem, retells the myth of Heracles’ tenth labor and the deaths of Geryon and Orthus. It was very highly regarded in antiquity but now survives only in fragments.

  • Apollodorus (first century BCE/first few centuries CE): The Library, a mythological handbook incorrectly attributed to Apollodorus of Athens, contains a brief but important summary of the myth of Orthus and his connection with the tenth labor.

Secondary Sources


“Orthus.” Mythopedia, March 24, 2023.

“Orthus.” Mythopedia, 24 Mar. 2023. Accessed on 6 Jun. 2024.

(2023, March 24). Orthus. Mythopedia.