In Arthurian legend the Fisher King, or the Wounded King, is the last in a long line charged with keeping the Holy Grail. Versions of his story vary widely, but he is always wounded in the legs or groin and incapable of moving on his own. In the Fisher King legends, he becomes impotent and unable to perform his task himself, and he also becomes unable to father or support a next generation to carry on after his death. His kingdom suffers as he does, his impotence affecting the fertility of the land and reducing it to a barren wasteland. All he is able to do is fish in the river near his castle, Corbenic, and wait for someone who might be able to heal him. Healing involves the expectation of the use of magic. Knights travel from many lands to heal the Fisher King, but only the chosen can accomplish the feat. This is Percival in earlier stories; in later versions, he is joined by Galahad and Bors.
Many works have two wounded "Grail Kings" who live in the same castle, a father and son (or grandfather and grandson). The more seriously wounded father stays in the castle, sustained by the Grail alone, while the more active son can meet with guests and go fishing. For the purposes of clarity in the remainder of this article, where both appear, the father will be called the Wounded King, the son the Fisher King.
The Fisher King appears first in Chrétien de Troyes' Perceval (late 12th-century), but the character's roots may lie in Celtic mythology. He may be derived more or less directly from the figure of Bran the Blessed in the Mabinogion. In the Second Branch, Bran has a cauldron that can resurrect the dead (albeit imperfectly; those thus revived cannot speak) which he gives to the king of Ireland as a wedding gift for him and Bran's sister Branwen. Later, Bran wages war on the Irish and is wounded in the foot or leg, and the cauldron is destroyed. He asks his followers to sever his head and take it back to Britain, and his head continues talking and keeps them company on their trip. The group lands on the island of Gwales (perhaps Grassholm), where they spend 80 years in a castle of joy and abundance, but finally they leave and bury Bran's head in London. This story has analogues in two other important Welsh texts: the Mabinogion tale Culhwch and Olwen, in which King Arthur's men must travel to Ireland to retrieve a magical cauldron, and the obscure poem The Spoils of Annwn, which speaks of a similar mystical cauldron sought by Arthur in the otherworldly land of Annwn.