Question: The character played by Michael Gambon in the "Harry Potter" series was the founder of what organization?

full_context: Document 1: Patrick Stewart: Sir Patrick Stewart {'1': ", '2': ", '3': ", '4': "} (born 13 July 1940) is an English actor whose career has included roles on stage, television, and film in a career spanning almost six decades. He is a multiple time Olivier, Golden Globe, Emmy, Screen Actors Guild and Saturn Award nominee.
Document 2: Order of the Phoenix (fictional organisation): The Order of the Phoenix is a secret organisation in the "Harry Potter" series of fiction books written by J. K. Rowling. Founded by Albus Dumbledore to fight Lord Voldemort and his followers, the Death Eaters, the Order lends its name to the fifth book of the series, "Harry Potter and the Order of the Phoenix".
Document 3: Albus Dumbledore: Professor Albus Percival Wulfric Brian Dumbledore is a fictional character in J. K. Rowling's "Harry Potter" series. For most of the series, he is the headmaster of the wizarding school Hogwarts. As part of his backstory, it is revealed that he is the founder and leader of the Order of the Phoenix, an organisation dedicated to fighting Lord Voldemort.
Document 4: Richard Harris: Richard St John Harris (1 October 1930 – 25 October 2002) was an Irish actor and singer. He appeared on stage and in many films, appearing as Frank Machin in "This Sporting Life", for which he was nominated for the Academy Award for Best Actor, King Arthur in the 1967 film "Camelot" and the subsequent 1981 revival of the show. He played an aristocrat and prisoner in "A Man Called Horse" (1970), a gunfighter in Clint Eastwood's Western film "Unforgiven" (1992), Emperor Marcus Aurelius in "Gladiator" (2000), and Albus Dumbledore in the first two "Harry Potter" films: "the Philosopher's Stone" (2001) and "the Chamber of Secrets" (2002). Harris had a number one hit in Australia and Canada and a top ten hit in the United Kingdom and United States with his 1968 recording of Jimmy Webb's song "MacArthur Park".
Document 5: Ian McKellen: Sir Ian Murray McKellen, {'1': ", '2': ", '3': ", '4': "} (born 25 May 1939) is an English actor. He is the recipient of six Laurence Olivier Awards, a Tony Award, a Golden Globe Award, a Screen Actors Guild Award, a BIF Award, two Saturn Awards, four Drama Desk Awards, and two Critics' Choice Awards. He has also received two Oscar nominations, four BAFTA nominations and five Emmy Award nominations.
Document 6: Dumbledore's Army: Dumbledore's Army (or D.A. for short) is a fictional student organisation in J. K. Rowling's "Harry Potter" series that is founded by the main characters, Harry Potter, Ron Weasley and Hermione Granger, to stand up against the regime of Hogwarts High Inquisitor Dolores Umbridge, as well as to learn practical Defence Against the Dark Arts. It was founded in the fifth book, "Harry Potter and the Order of the Phoenix". Cho Chang conceives of the abbreviation "D.A." and Ginny Weasley conceives of the name "Dumbledore's Army".
Document 7: Michael Caine: Sir Michael Caine {'1': ", '2': ", '3': ", '4': "} ( ; born Maurice Joseph Micklewhite Jr., 14 March 1933) is an English actor, producer, and author. Renowned for his distinctive working class cockney accent, Caine has appeared in over 115 films and is regarded as a British film icon.
Document 8: Severus Snape: Severus Snape is a fictional character in J. K. Rowling's "Harry Potter" series. An exceptionally skilful wizard, his coldly sarcastic and controlled exterior conceals deep emotions and anguish. A Professor at Hogwarts School of Witchcraft and Wizardry, Snape is hostile to the series' protagonist, Harry, the moment he sets foot in Snape's classroom; this hostility is rooted in Harry's resemblance to Harry's father James, who bullied and harassed Snape during their time at Hogwarts. Though philosophically attracted to the Dark Arts and Lord Voldemort's ideology of wizard supremacy, Snape's love for Muggle-born Lily Evans, Harry's mother, eventually compels him to defect from the Death Eaters. Snape becomes a double-agent on behalf of Albus Dumbledore and the Order of the Phoenix, and protects Harry throughout the series.
Document 9: Michael Gambon: Sir Michael John Gambon {'1': ", '2': ", '3': ", '4': "} (born 19 October 1940) is an Irish-born English actor who has worked in theatre, television and film. Gambon has played the eponymous mystery writer protagonist in the BBC television serial "The Singing Detective", Jules Maigret in the 1990s ITV serial "Maigret", and Professor Albus Dumbledore in the final six "Harry Potter" films after the death of previous actor Richard Harris. He has won four BAFTA TV Awards and three Olivier Awards.
Document 10: Elizabeth Burke: Elizabeth Burke, (fictional) Headmaster at Hogwarts by JK Rowling
Document 11: Alan Cumming: Alan Cumming, OBE (born 27 January 1965), is a Scottish-American actor, singer/performer, author, and activist who has appeared in numerous films, television shows, and plays. His London stage appearances include "Hamlet", the Maniac in "Accidental Death of an Anarchist" (for which he received an Olivier Award), the lead in "Bent", and the National Theatre of Scotland's "The Bacchae". On Broadway, he has appeared in "The Threepenny Opera", as the master of ceremonies in "Cabaret" (for which he won a Tony Award), "Design for Living" and a one-man adaptation of "Macbeth". His best-known film roles include his performances in "Emma", "GoldenEye", the "Spy Kids" trilogy, "Son of the Mask," and "X2". Cumming also introduces "Masterpiece Mystery!" for PBS and appeared on "The Good Wife", for which he has been nominated for three Primetime Emmy Awards, two Screen Actors Guild Awards, two Golden Globe Awards and a Satellite Award. A filming of his Las Vegas cabaret show, "Alan Cumming Sings Sappy Songs", aired on PBS stations in November 2016.
Document 12: The Singing Detective: The Singing Detective is a BBC television serial drama, written by Dennis Potter, which stars Michael Gambon and was directed by Jon Amiel. The six episodes were "Skin", "Heat", "Lovely Days", "Clues", "Pitter Patter" and "Who Done It".
Document 13: Rubeus Hagrid: Rubeus Hagrid is a fictional character in the "Harry Potter" book series written by J. K. Rowling. He is introduced in "Harry Potter and the Philosophers Stone" as a half-giant and half-human who is the gamekeeper and Keeper of Keys and Grounds of Hogwarts, the primary setting for the first six novels. In the third novel "Harry Potter and the Prisoner of Azkaban", Hagrid is promoted to Care of Magical Creatures teacher, and is later revealed to be a member of the Order of the Phoenix.
Document 14: Harry Potter (character): Harry James Potter is the title character and protagonist of J. K. Rowling's "Harry Potter" series. The majority of the books' plot covers seven years in the life of the orphan Potter, who, on his eleventh birthday, learns he is a wizard. Thus, he attends Hogwarts School of Witchcraft and Wizardry to practise magic under the guidance of the kindly headmaster Albus Dumbledore and other school professors. Harry also discovers that he is already famous throughout the novel's magical community, and that his fate is tied with that of Lord Voldemort, the internationally feared Dark Wizard and murderer of his parents, Lily and James.
Document 15: Ian McKellen, roles and awards: Ian McKellen (born 25 May 1939) is an English stage and screen actor. He is the recipient of six Laurence Olivier Awards, a Tony Award, a Golden Globe Award, two Academy Award nominations, four BAFTA nominations and five Emmy Award nominations. McKellen's work spans genres ranging from Shakespearean and modern theatre to popular fantasy and science fiction. His notable film roles include Gandalf in "The Lord of the Rings" and "The Hobbit" trilogies, Magneto in the "X-Men" films, Sir Leigh Teabing in "The Da Vinci Code" (2006), Sherlock Holmes in "Mr. Holmes" (2015) and Cogsworth in "Beauty and the Beast" (2017).
ground_truth: Order of the Phoenix