Io herself wasn't a goddess at first, although in some legends, she became one. She was a priestess of Argive Hera, and the daughter of River god Inachus. She had become one of Zeus's many consorts, and to hide her from Hera, Zeus changed the girl into a heifer. But Hera had grown suspicious of Zeus's liking to this particular cow and she ordered the hundred-eyed Argus to guard it. Zeus became worried and told his son Hermes to kill Argus. Hermes obeyed his father, going to the field where Argus guarded Io. He then pulled out his lyre and played so sweetly that each of Argus's eyes closed as he fell asleep. Hermes then slayed the monster, setting Io free. When Hera found out what had happened, she sent a gadfly after the heifer. Io was so frightened that she ran and ran until she reached a great body of water. To escape Hera's wrath, she swam to Egypt, where she was transformed back into a beautiful girl and where she became the goddess, Isis. Or, in some cases, founded the worship of Isis, whom she called Demeter. Her son was the King of Egypt, Epaphus. Epaphus had a daughter, Libya, who was the mother by Poseidon by Agenor and Belus. She was known as different goddesses in different places. Primarily, a love and magic goddess.