Sir Yvain (also called Owain, Ywain, Ewain or Uwain) is a Knight of the Round Table in the Arthurian legend. He is purported to be the son of King Urien. The character is thought to be based on Owain mab Urien, who was the king of Rheged in Great Britain during the late 6th century.
"Yvain, the Knight of the Lion" is a well known and documented story of a Sir Yvain in King Arthur's court. Before being known as the Knight of the Lion, Sir Yvain went on a mission to revenge the brother-in-law of King Arthur—and to win fame for himself. This trip lead to several more and, in the course of his travels, he jousted various knights, fought a few monsters, fell in love with a widow queen, lost his sanity—albeit shortly—and save helpless women.