This card must be Tribute Summoned by offering 3 Winged Beast-Type monsters on your side of the field as Tributes.

只能用自己场上3只鸟族怪兽作为祭品进行祭品召唤出场。

youdao

But, riding his winged horse, Pegasus, Bellerophon instead emerged victorious from his battle with the beast (winning the hand of Iobates' daughter and eventually his kingdom).

WSJ: The Imaginary Made Nearly Read | The Chimera of Arezzo | Masterpiece by Judith H. Dobrzynski