A cyclops (/ˈsaɪklɒps/ SY-klops; Ancient Greek: Κύκλωψ, Kyklōps; plural cyclopes /saɪˈkloʊpiːz/ sy-KLOH-peez; Ancient Greek: Κύκλωπες, Kyklōpes), in Greek mythology and later Roman mythology, was a member of a primordial race of giants, each with a single eye in the center of his forehead. The word "cyclops" literally means "round-eyed" or "circle-eyed".
Hesiod described three one-eyed cyclopes, Brontes, Steropes and Arges, the sons of Uranus and Gaia, brothers of the Titans, builders and craftsmen, while the epic poet Homer described another group of mortal herdsmen cyclopes the sons of Poseidon. Other accounts were written by the playwright Euripides, poet Theocritus and Roman epic poet Virgil. In Hesiod's Theogony, Zeus releases three cyclopes from the dark pit of Tartarus. They provide Zeus' thunderbolt, Hades' helmet of invisibility, and Poseidon's trident, and the gods use these weapons to defeat the Titans.
In a famous episode of Homer's Odyssey, the hero Odysseus encounters the cyclops Polyphemus, the son of Poseidon and Thoosa, who lives with his fellow cyclopes in a distant country. The connection between the two groups has been debated in antiquity and by modern scholars. It is upon Homer's account that Euripides and Virgil based their accounts of the mythical creatures. Strabo describes another group of seven Lycian cyclopes, also known as "Bellyhands" because they earned from their handicraft. They had built the walls of Tiryns and perhaps the caverns and the labyrinths near Nauplia, which are called cyclopean.
Walter Burkert among others suggests that the archaic groups or societies of lesser gods mirror real cult associations: "It may be surmised that smith guilds lie behind Cabeiri, Idaian Dactyloi, Telchines, and Cyclopes." Given their penchant for blacksmithing, many scholars believe the legend of the cyclopes' single eye arose from an actual practice of blacksmiths wearing an eyepatch over one eye to prevent flying sparks from blinding them in both eyes. The cyclopes seen in Homer's Odyssey are of a different type from those in the Theogony and they have no connection to blacksmithing. It is possible that independent legends associated with Polyphemus did not make him a cyclops before Homer's Odyssey; Polyphemus may have been some sort of local daemon or monster in original stories.
Another possible origin for the cyclops legend, advanced by the paleontologist Othenio Abel in 1914, is the prehistoric dwarf elephant skulls – about twice the size of a human skull – that may have been found by the Greeks on Cyprus, Crete, Malta and Sicily. Abel suggested that the large, central nasal cavity (for the trunk) in the skull might have been interpreted as a large single eye-socket. Given the inexperience of the locals with living elephants, they were unlikely to recognize the skull for what it actually was.
Veratrum album, or white hellebore, an herbal medicine described by Hippocrates before 400 BC, contains the alkaloids cyclopamine and jervine, which are teratogens capable of causing cyclopia and holoprosencephaly, severe birth defects in which a fetus can be born with a single eye. Students of teratology have raised the possibility of a link between this developmental deformity in infants and the myth for which it was named. Regardless of the connection between the herb and the birth abnormalities, it is possible these rare birth defects may have contributed to the myth. However, a study of deformed humans born with a single eye all have a nose above the single eye, not below. This weakens the idea that the myth was based on deformed humans, since the stories have the single eye above the nose, unlike the actual examples that have been studied.
Using phylogenetics tools, Julien d'Huy has reconstructed the history and prehistory of the versions of Polyphemus back to the Paleolithic period.
After the "Dark Age", when Hellenes looked with awe at the vast dressed blocks, known as Cyclopean structures, which had been used in Mycenaean masonry (at sites such as Mycenae and Tiryns or on Cyprus), they concluded that only the cyclopes had the combination of skill and strength to build in such a monumental manner.