"Monty Python and the Holy Grail" is a classic 1975 British comedy film written and performed by the comedy group Monty Python. The principal cast members and the main roles they played are as follows: 1. Graham Chapman as King Arthur, leader of the quest for the Holy Grail. Chapman also played the voice of God and the Middle Head of the Three-Headed Giant. 2. John Cleese as Sir Lancelot the Brave, one of Arthur's knights. Cleese also portrayed several other characters, including the French Taunter, the Black Knight, and Tim the Enchanter. 3. Terry Gilliam played Patsy, King Arthur’s assistant and coconut clapper, along with several smaller roles such as the Green Knight and one of the bridge keepers. Gilliam was also the film's co-director and animator of its distinctive interstitial sequences. 4. Eric Idle as Sir Robin the Not-Quite-So-Brave-as-Sir Lancelot. Idle also appeared as the Dead Collector, Concorde (Lancelot’s squire), and other characters. 5. Terry Jones portrayed Sir Bedevere the Wise, one of Arthur's knights known for his "scientific method." Jones also played Prince Herbert and other parts, as well as co-directing the film. 6. Michael Palin as Sir Galahad the Pure. Palin also played several other characters, including King of Swamp Castle, the Leader of The Knights who say Ni, and the narrator. Each member of the iconic Monty Python team played multiple roles throughout the film, showcasing their versatility as comedic actors. These performances contributed to the cult status of the movie which continues to entertain audiences across generations.