The Order of the Phoenix was a secret organization founded by Albus Dumbledore. The Order's main goal was to prevent Voldemort from taking control of the wizarding world, protecting both wizards and Muggles from his tyranny. The Order's plan was to weaken the Death Eaters and discover the Horcruxes. The members were: Sirius Black, Remus Lupin, Tonks, Alastor "Mad-Eye" Moody, and the Weasleys. The headquarters were at 12 Grimmauld Place, where its plans and operations were organized in secret.