Bellerophon was the tamer of the flying horse Pegasus and heroic vanquisher of the Chimaera, a monster so fantastic that it has entered our language in the adjective chimerical, describing the improbable product of a wild imagination.
Bellerophon was a citizen of Corinth who was exiled owing to a murder which he had committed. In those days it was possible to be purified of the guilt of such a crime, and Bellerophon was in due course absolved by King Proetus of neighboring Tiryns. The king's wife, generally identified as Stheneboea, made a pass at the young hero, and when he repulsed her advances she told her husband that it was Bellerophon who made a pass at her.
King Proetus cloaked his indignation, not wishing to violate the sacred obligations of hospitality by doing harm to his guest. But he contrived his revenge by asking Bellerophon to deliver a letter on his behalf to King Iobates of Lycia, his father-in-law. This is somewhat surprising in that writing hadn't been invented yet, except perhaps a rudimentary form used for inventory-keeping on the island of Crete and certain parts of the mainland. No wonder Bellerophon couldn't make out the meaning of the message he was to deliver. Either that or the letter was sealed - although for that matter "letters" hadn't been invented yet either.
What the message said was: "Dear Iobates, please do me a favor and kill the person who hands you this." To do so proved impossible, however, as Iobates was bound by the same strictures of hospitality as King Proetus. So instead he feasted Bellerophon for a goodly number of days and nights, until at length he announced that he had a favor to ask of him. Assuming that this had something to do with a return letter to Proetus, Bellerophon may well have been giving thought to establishing the first postal service, when Iobates surprised him with the unexpected nature of his request. Would Bellerophon be so kind as to rid the kingdom of the Chimaera?
Not wishing to sugarcoat the challenge, the king went on to describe the Chimaera as a fire-breathing monster directly related to Heracles' nemesis the many-headed Hydra, and Cerberus, watchdog of Hades. The Chimaera had a lion's front, a goat's middle and a snake's tail (or, in some alternative versions of the myth, the heads of these three beasts with some admixture of body parts). In any case, it was truly ferocious.
Iobates was hoping to make good on his son-in-law's request to do away with Bellerophon, and he had hit upon the Chimaera as the ideal agent in expediting his young guest's demise. And while one might think that he would have made little of the Chimaera's dangers in order to instill a false sense of security, Iobates had sized up Bellerophon and deduced that he was a sucker for a challenge - the bigger the better. And in fact Bellerophon was pleased at the opportunity to elevate himself from mere postal-delivery person to authentic hero. He immediately began to plan his campaign of attack.
Word was that the Chimaera was virtually impregnable to any ground assault. Others had waded in on foot with spear or sword - to their eternal regret. There was even a rumor of a mounted Thessalian who had come up short in the encounter, his horse having been blasted out from under him by the Chimaera's fiery breath. With a keen sense of logistics, Bellerophon narrowed down his viable options to an attack either by air or sea. The latter course being out by virtue of the inland nature of the Chimaera's lair, he settled on the aerial option and immediately set out to procure himself a winged steed.
When Bellerophon was still a boy growing up in Corinth, he had yearned to ride the magic horse Pegasus, immortal offspring of the god Poseidon and the Gorgon Medusa. Pegasus was born when the hero Perseus cut off Medusa's head. Like everyone else, Bellerophon had been unable to so much as approach Pegasus. So he sought the advice of the seer Polyeidus.
Polyeidus suggested that Bellerophon spend the night in Athena's temple. In a dream, the goddess came to him and gave him a golden bridle. And in the morning Bellerophon found Pegasus drinking at the spring of Peirene and slipped the bridle over his head, rendering him tame and rideable. Thus once more, in manhood, Bellerophon sought out the Corinthian watering hole and his trusty mount, and as he did so he gave thought to the essential issue of armament.
Clearly not just any sword or spear would do in fighting the Chimaera. For starters, a lance would be indispensable - the sort of spear best suited to fighting on horseback. And even a proper lance was no guarantee of victory over so substantial a foe.
Again the gods came to Bellerophon's aid, suggesting that a lump of lead affixed to the end of the spear would have a decidedly deadly effect. Firstly, when thrust into the monster's maw, it would cause the Chimaera to gag. And secondly, when melted by the beast's fiery breath, it would trickle down into its innards and cause a fatal case of heartburn.
So Bellerophon trekked all the way from Lycia to Corinth, located the fountain of Peirene and found Pegasus sipping therefrom. Mounting up, the hero made a much speedier trip back to Lycia, swooped down on the Chimaera's lair and rammed home the secret weapon. And with a great, gasping groan of rage, the Chimaera gave up the ghost.