In ancient Greece, people believed in dragons. One very known myth is about the golden apples of Hesperides. Those fruits were given to Zeus and Hera as a wedding gift from the mother goddess earth. Hera kept the trees with the golden fruits into the Garden of Gods and ordered to a dragon guard them. That dragon looked like a huge snake with many heads. The dragon was sleepless because when some of the heads were sleeping others were keeping open eyes. Nobody could approach and steal the fruits.
According to myth, that dragon was killed by Hercules, who wanted to steal the golden apples. Then Zeus turned the dragon into a constellation to thank him for his service and forced Hercules to give back the golden fruits.