Apollodorus, Library and Epitome 2.3.2
Pegasus, offspring of Medusa and Poseidon
View the Perseus Text

2.3.2
So Bellerophon mounted his winged steed Pegasus, offspring of Medusa and Poseidon, and soaring on high shot down the Chimera from the height. After that contest Iobates ordered him to fight the Solymi, and when he had finished that task also, he commanded him to combat the Amazons. And when he had killed them also, he picked out the reputed bravest of the Lycians and bade them lay an ambush and slay him. But when Bellerophon had killed them also to a man, Iobates, in admiration of his prowess, showed him the letter and begged him to stay with him; moreover he gave him his daughter Philonoe, and dying bequeathed to him the kingdom.