Iris- Goddess of the Rainbow

This is my favorite picture of Iris

Iris was the minor goddess (or personification) of the rainbow. She was the daughter of Thaumas, god of the wonders of the sea, and Electra, princess of Argos,  who also gave birth to Iris' lovely sisters, the Harpies.
She was never married, but she always had a thing going for Zephyrus, god of the west wind. Together they had Pothos, the god of yearning.
Iris had the job of Messenger on Mount Olympus. She shared her role with Hermes. Although she delivered messages for all the gods, she was especially partial to Hera, who soon adopted Iris as her personal messenger. When delivering messages Iris was thought to either ride on a rainbow, or become a rainbow. And when she was delivering messages to mortals she always took the form of someone they were familiar with.
Iris had a special job to go along with being Messenger. Whenever the gods wanted to swear an oath, they required water from the river Styx. If you were to break an oath sworn by the river Styx, well, you would suffer dire consequences. If you were to drink the water, you would be revealing your secrets to the world. By drinking it you could tell if a person was telling the truth. If you swam in the waters you could become invincible (to a point, see the story of Achilles). It was Iris' job to fetch the water when it was needed. Not another god wanted to go down to the Underworld to get it, and Zeus only trusted Iris with this job.
Her sacred symbols/animals are a golden pitcher, golden wings, or a staff. She is often depicted as a beautiful woman or a rainbow.

When Jason and the Argonaughts were on a quest to find the golden fleece, they needed information. They came across Phineas, a blind seer. Phineas was cursed to always have his food stolen by the hideous and smelly Harpies, sisters to Iris. Phineas told the Argonaughts that he would only give them the promised info if they would rid him of the Harpies. So the Argonaughts, being violent men, drew their swords and attacked the Harpies. But Iris wouldn't allow it. Before they could reach the ugly bird-women, Iris stopped the Argonaughts and told them that If they didn't kill the Harpies, her sisters would never bother Phineas again.