Who was Ixion?

In Greek mythology, Ixion is the king of the Lapithae. According to Greek tradition he was the first murderer of a kinsman. Married to Dia, the daughter of Eïoneus, Ixion refused to pay his father-in-law the promised bride-price and had him killed. Since no mortal consented to cleanse him of his crime, Zeus, the ruler of the gods, carried Ixion to Olympus to be purified. Ungrateful and impious, Ixion made improper advances to Hera, queen of the gods. In revenge, Zeus created a cloud in Hera's shape, by which Ixion fathered the monster race of centaurs. Ixion was then punished by being chained to a fiery wheel, which re¬volved perpetually in Hades.