The eagle was the king of the birds, under the dominion of the supreme god Zeus (the god of sky). The eagle was the royal servant and a fighter.

One of the myth about the eagle was the abduction and seduction by Zeus of a beautiful boy, Ganymede. Ganymede is the prince of Troy who was said to be the most beautiful youth alive. Hebe, the original cup-bearer gave up her pose when she was married to Hercules. Zeus either disguised himself or send his royal servant, Aquila to take Ganymede to Mount Olympus as the new cup-bearer. And the eagle is then put on the sky. 

Another myth concerns about the eagle is when Prometheus was punished by Zeus. Prometheus was chained naked to a pillar on the Caucasus Mountains, and the eagle of Zeus tore through his flesh to his liver from dawn to dusk. Because Prometheus was an immortal, his liver healed every night, but to be tore out again when the eagle appear again the next dawn. He is supposed to suffer like this forever. Eventually, many years later, Hercules show mercy to Prometheus. The wise centaur Chiron agreed to exchange his immortality for Prometheus' freedom. After Zeus had relented, Hercules shot the eagle through his heart.