The Fisher King is a comedy-drama film made in 1991, written by Richard LaGravenese and directed by Terry Gilliam. It starred Jeff Bridges, Robin Williams, Mercedes Ruehl, Amanda Plummer and Michael Jeter. The film is about a radio shock-jock who tries to find redemption by helping a homeless man whose life he inadvertently shattered.

The title refers to the legend of the Fisher King, a form of which Parry recounts to Lucas. The legend varies, but all iterations possess three elements: the Fisher King was charged by God with guarding the Holy Grail, but later incurred some form of incapacitating physical punishment for his sin of pride, and had to wait for someone to deliver him from his suffering. This was usually Percival, who was also referred to in the movie as "The Fool", with the closing exchange, "I've sent my brightest and bravest men to search for this. How did you find it?" The Fool laughed and said "I don't know. I only knew that you were thirsty." Echoes of the legend recur throughout the film, but in a continually shifting manner, so that it sometimes appears that Lucas is Percival to Parry's Fisher King, sometimes vice versa, and sometimes that one or the other is re-enacting part of the story with another character (most obviously in Parry's self-assigned quest to obtain the Grail from the man he believes is its guardian).

A central theme of the film, playing on the grail motif, is grace and forgiveness. Jack's signature line in his potential sitcom is "forgive me," which he is constantly repeating but can't get right. Parry is seeking the Holy Grail, which held the wine of the Last Supper and, at the crucifixion, its theological equivalent, the blood of Christ - the very source of grace and forgiveness. The Red Knight figment that Parry sees around New York seems to represent Parry's fears from both his former life as a medieval history professor, his time in the mental institution and his current life as a homeless dreamer on the street, all of which send him into a catatonic state. (The Red Knight could also represent the image of Parry's wife dying in front of him. She was shot in the back of the head with a shotgun while facing him.) In Wolfram Von Eschenbach's epic Parsival, the Red Knight was killed by Parsival (Perry) who then took took his armor for himself. When Parsival introduces himself to King Arthur's court, Arthur names Parsival the new Red Knight.

Source: Wikipedia