Hesiod, in the "Theogony" (c. 700 BC), described three Cyclopes: Brontes, Steropes, and Arges, who were the sons of Uranus (Sky) and Gaia (Earth), and the brothers of the Titans and Hundred-Handers, and who had a single eye set in the middle of their foreheads. They made for Zeus his all-powerful thunderbolt, and in so doing, the Cyclopes played a key role in the Greek succession myth, which told how the Titan Cronus overthrew his father Uranus, and how in turn Zeus overthrew Cronus and his fellow Titans, and how Zeus was eventually established as the final and permanent ruler of the cosmos. The names that Hesiod gives them: Arges (Bright), Brontes (Thunder), and Steropes (Lightning), reflect their fundamental role as thunderbolt makers. As early as the late seventh-century BC, the Cyclopes could be used by the Spartan poet Tyrtaeus to epitomize extraodinary size and strength.