Perseus is the son of Zeus and Danaë, only child and daughter of King Acrisius of Argos. He was known as the slayer of the Gorgon Medusa. Before his birth, it was predicted by the oracle of Apollo that he would kill his grandfather. King Acrisius first locked Danaë in a bronze house, but Zeus saw the beautiful Danaë and visited her in the form of showers of gold (because the bronze house was sunk underground and only part of the roof was left open). Danaë became pregnant and kept it secret to her father, but soon it was discovered (when Perseus was a young child). When Acrisius found out about the boy, Danaë told to him that Perseus was her son to Zeus. Even though the young Perseus was the son of Zeus, Acrisius was still afraid of the prediction about the young boy, so Acrisius locked the mother and son into a chest and floated them in the sea.
Perseus and his mother drifted to an island called Seriphus and was discovered, still inside the chest, by a fisherman named Dictys. Dictys took them in to his home where he lived with his wife, and they were treated as his family.
The ruler of the island, Polydectes, fell in love with Danaë and thought that Perseus would hinder his plan to marry her. He thought of a plan that would get rid of Perseus: He announce that he will marry Danaë and invited all his friends to a celebration. Perseus was among the guests. Each guest should have a present for the celebration, but Perseus had nothing to give. Polydectes asked Perseus to slay and behead the Gorgon Medusa and bring back her head as his gift. Perseus agreed to do so.
He received a mirror-like shield to take on his journey. Because the Gorgons could turn anybody to stone by looking in their eyes, Perseus cleverly looked in the shield, so that Medusa couldn't look directly into his eyes.