A running battle is fought between members of the D.A., a group of Death Eaters, and members of the Order of the Phoenix. Sirius Black is killed and many others are wounded (OP35). When Voldemort himself arrives and battles Dumbledore in the Atrium, Fudge is forced to admit that Voldemort has indeed returned and remove Umbridge from Hogwarts (OP36). Dumbledore returns to Hogwarts and reveals to Harry the contents of Trelawney’s first prophecy (OP37).
June 18, 1996
Death Eaters cornered a group of Hogwarts students in the Hall of Prophecy after the teenagers had been lured there by Lord Voldemort. The students were led by Harry Potter while the Death Eaters were under the direction of Lucius Malfoy. The students, who were part of the group called the DA, or Dumbledore’s Army, suffered numerous injuries in a running battle through the various rooms of the Department of Mysteries but inflicted damage on their enemies as well. However, they had nearly been defeated when a contingent from the Order of the Phoenix arrived and turned the tide of battle in the Death Chamber. Finally, Dumbledore arrived and captured nearly all the Death Eaters. Lord Voldemort himself then Apparated into the Ministry of Magic, unaware that his archnemesis was present, and he and Dumbledore fought a tremendous duel in the Atrium. Voldemort was defeated in this duel and fled with Bellatrix Lestrange. Many were wounded on both sides and Sirius Black of the Order of the Phoenix was killed (OP34-36).
Order of the Phoenix
Sirius Black (killed)
Lucius Malfoy (leader)
The date of the battle was given on Pottermore, which listed the date of Sirius Black's death.