Albus Dumbledore is the founder of the order of the Phoenix. The Order of the Phoenix is an organization in the Harry Potter series. The fifth book of the Harry Potter series (Harry Potter and the Order of the Phoenix) got its name from the Order.
The organization was founded in order to fight lord Voldemort and his followers, the Death Eaters.
This secret organization comprises of several characters such as Mad-eye Moody, Nymphadora tonks, Remus Lu, Mineerva McGonagall, Edgar Bones, Caradoc Dearborn, Aberforth Dumbledore, Sirius Black and Albus Dumbledore the founder and headmaster of Hogwarts School of witchcraft and wizardry.