Order of the Phoenix
The Order of the Phoenix is a secret organisation in the Harry Potter series written by J. K. Rowling. The organisation was created by Albus Dumbledore to fight Lord Voldemort and his followers, the Death Eaters, the Order lends its name from the fifth book of the Harry Potter series, Harry Potter and the Order of the Phoenix.
The headquarters of the Order is located at Number Twelve, Grimmauld Place, Sirius Black's family home. Dumbledore was the Secret-Keeper for the Order, meaning that only he could tell others the location of headquarters. Dumbledore's death in book six, Harry Potter and the Half-Blood Prince, made the location unsafe and the headquarters was moved to The Burrow as a result.