Zeus's five siblings. Zeus then fights a similar ten-year war against the Titans, until, upon the prophesying of Gaia, he releases the Cyclopes and Hundred-Handers from Tartarus, first slaying their warder, Campe. The Cyclopes give him his thunderbolt, Poseidon his trident and Hades his helmet of invisibility, and the Titans are defeated and the Hundred-Handers made their guards. According to the Iliad, after the battle with the Titans, Zeus shares the world with his brothers, Poseidon and Hades, by drawing lots: Zeus receives the sky, Poseidon the sea, and Hades the underworld, with the earth and Olympus remaining common ground. Challenges to Power Upon assuming his place as king of the cosmos, Zeus' rule is quickly challenged. The first of these challenges to his power comes from the Giants, who fight the Olympian gods in a battle known as the Gigantomachy. According to Hesiod, the Giants are the offspring of Gaia, born from the drops of blood that fell on the ground when Cronus castrated his father Uranus; there is, however, no mention of a battle between the gods and the Giants in the Theogony. It is Apollodorus who provides the most complete account of the Gigantomachy. He says that Gaia, out of anger at how Zeus had imprisoned her children, the Titans, bore the Giants to Uranus. There comes to the gods a prophecy that the Giants cannot be defeated by the gods on their own, but can be defeated only with the help of a mortal; Gaia, upon hearing of this, seeks a special pharmakon (herb) that will prevent the Giants from being killed. Zeus, however, orders Eos (Dawn), Selene (Moon) and Helios (Sun) to stop shining, and harvests all of the herb himself, before having Athena summon Heracles. In the conflict, Porphyrion, one of the most powerful of the Giants, launches an attack upon Heracles and Hera; Zeus, however, causes Porphyrion to become lustful for Hera, and when he is just about to violate her, Zeus strikes him with his thunderbolt, before Heracles deals the fatal blow with an arrow. In the Theogony, after Zeus defeats the Titans and banishes them to Tartarus, his rule is challenged by the monster Typhon, a giant serpentine creature who battles Zeus for control of the cosmos. According to Hesiod, Typhon is the offspring of Gaia and Tartarus, described as having a hundred snaky fire-breathing heads. Hesiod says he "would have