Perseus

Perseus (Greek: Περσεύς) was a famous hero in Greek mythology. He was the son of Zeus and Danae, making him a Demigod, and is known best for having slain the creature Medusa. He is also the grandfather/half-brother of Heracles.

Birth
The King of Argos, Acrisius, visited the oracle of Delphi, in the hopes of having a male heir. However, upon arrival, he was shocked about what  the oracle said. He will be killed by his grandson. Acrisius promptly had his only daughter, Danae, imprisoned in a tower. However, Zeus, seeing Danae and stirred by her beauty, disguised himself as a shaft of golden sunlight and impregnated her. Acrisius, on finding out the news, contemplated his next move. For, if he were to murder his daughter, he would be cursed by the gods, particularly Zeus. He then decided to have her locked up in a chest and thrown into the sea. Danae prayed to Zeus to save her and her son. Zeus guided the chest onto the beach of the island of Seriphos, where she was found by a fisherman named Dictys. Dictys was the brother of Polydectes, King of the island. However, he preferred a much humbler and simpler life than his brother. Polydectes saw Danae and decided to marry her. However, Perseus, who grew into a strong, young man, opposed him.

The Quest for Medusa's Head
The next day, Polydectes held a feast. All his male subjects were ordered to bring a gift to the feast. Because Perseus was poor, he didn't have anything to give at the feast. Polydectes exiled him and ordered him to return only upon killing the only mortal Gorgon, Medusa, and bring back her head as a gift. He expected Perseus to die on this quest so he could live with his new wife in peace.

As soon as Perseus was out of sight of any mortals, two gods appeared: Hermes and Athena. Hermes gave Perseus a sword to slay the Gorgons with, and Athena presented him with a highly-polished shield - he was told to use this as a mirror, because if he looked directly at any of the Gorgons, he would be turned to stone. She also told him to go west and find the Gorgon's sisters, the Graeae - they were the only ones who knew where the Gorgons were. The Graeae (literally "gray ones") were three sister born as old ladies and shared a single eye and tooth amongst themselves. Perseus took the eye from them and threatened to pop it between his fingers if they didn't tell them where the Gorgons lived. They told him it was a swampy island with hardly any light, but just enough to see.

Before Perseus traveled to the island of the Gorgons, he first went to the land of Hyperborea where he received three special items: a magic wallet (to place Medusa's severed head in once she's vanquished), a pair of winged sandals (to travel back to his home), and an invisible cap (to hide himself from her immortal sisters, Euryale and Sthenno ).

Perseus landed on the island to find the three Gorgons laying on the ground sleeping (courtesy of Hypnos). Using the shield as a mirror, Perseus approached the sleeping Gorgons. When he was close enough, he brought the sword down upon Medusa's head, severing it from the body and having it roll and wake the other Gorgons. From her blood sprang the winged horse, Pegasus, and his human brother Chrysaor. He stuffed her head in his pouch, but the remaining Gorgons woke and flew at Perseus. He hid himself from them using the cap of darkness and then, using his winged sandals, he flew back home. It is said that when Perseus flew across the desert in Egypt, Medusa's blood leaked from the purse and touched the sand and created the poisonous snakes that live there today.

He arrived home during his mother's forced wedding. Polydectes, furious upon the hero's return, ordered him to present the head as a wedding gift. Perseus yelled, "Mother, cover your eyes!" He then pulled Medusa's head out of his pouch and turned everyone to stone. He then went to Athena's temple and gave the goddess the shield with Medusa's image etched on it, which she named the Aegis. Then he threw Medusa's head into the ocean where it drifted across the sea, creating coral on the way.

Andromeda
On his way home from his quest, Perseus passed by the land of Aethiopia where he saw Andromeda, the daughter of Cepheus and Cassiopeia (king and queen of Aethiopis), chained to a rock by the sea. He freed her and killed the sea monster that was about to eat Andromeda by showing the monster Medusa's severed head, instantly turning it to stone. After saving the king's daughter and Aethiopia from the sea monster's wrath, the king gave consent to Perseus to marry Andromeda.

The sea monster was Cetus, sent by Poseidon in revenge for Cassiopeia saying Andromeda was more beautiful than his wife, Amphitrite.

Death of Acrisius
Perseus later returned to Greece, where he decided to compete in the Olympics, in Olympia. Also attending were many royals, in particular, King Acrisius. As Acrisius sat down in the stands, the discus event was beginning. Perseus, competing at the time, threw the discus with such force it flew into the stands and inadvertently killed Acrisius, thus fulfilling the oracle's prophecy. Perseus, in shame, traded his kingdom of Argos, for that of his cousin Megapenthes'. Thus Perseus, now King of Tiryns and Mycenae (which he founded), married Andromeda and had many children and grandchildren, who frequently intermarried with the descendants of Pelops.
 * Perses, later King of Aethiopia
 * Alcaeus, father of the hero Amphitryon and of Anaxo, by Astydaemia, daughter of Pelops
 * Mestor, father of Hippothoe (mother, by Poseidon, of Taphius, King of the Taphians ), by Lysidice, daughter of Pelops
 * Heleus, accompanied Amphitryon on his expeditions
 * Electryon, succeeded his father as King of Mycenae and Tiryns, father of Alcmene (mother of Heracles), by Anaxo, his niece
 * Sthelenus, succeeded his brother as King of Mycenae and Tiryns, father of Eurystheus (who succeeded his father as King) by Nicippe, daughter of Pelops
 * Autochthe, wife of King Aegeus of Athens
 * Gorgophone, wife of King Oebalus of Sparta, and mother of King Tyndareus, King Hippocoon and Icarius