Lord Voldemort created his fifth Horcrux using Hogwarts founder Rowena Ravenclaw's Diadem. The spell needed to create a horcrux was cast after Voldemort murdered an Albanian peasant. The diadem is introduced by Xenophilius Lovegood, father of Luna Lovegood, in The Deathly Hallows. Ravenclaw's daughter Helena, also known as The Grey Lady of Ravenclaw, stole the diadem from her mother in an attempt to become more intelligent than her own mother. She fled to Albania where she hid the diadem in the hollow of a tree when the Bloody Baron attempted to search for her.After Helena died, she became the Ravenclaw house ghost. Tom Riddle, while a student at the school, charmed the Lady into telling him the location of her mothers lost diadem. Shortly after leaving Hogwarts and after the subsequent murder of Hepzibah Smith where Riddle stole Slytherins Locket and Hufflepuffs cup from her, he travelled to Albania and took possession of the artifact while planning his rise to power. Years later, when Voldemort returned to Hogwarts and reapplied for the Defence Against the Dark Arts position and was denied the job by Albus Dumbledore, he hid the diadem Horcrux in the Room of Requirement. Voldemort believed himself to only have delved into Hogwarts's many secrets and thought the Horcrux to be safe and hidden, with the additional protection of the school and the room he never placed curses around the diadem.In Harry Potter and the Half Blood Prince, Harry first comes into contact with the diadem when he hastily hides the HalfBlood Prince's old potions book in the Room of Requirement, right after he used an invented spell from the book on Draco Malfoy. The diadem was only mentioned as an "old discoloured tiara" in the sixth book where Harry attempted to plan to try to later remember exactly where he placed the book. Later, after having the diadem described to him by the Ravenclaw ghost, Harry recalls this scene and hurries to retrieve it from the Room.The diadem was destroyed by a Fiendfyre spell cast by Vincent Crabbe as he, Gregory Goyle and Draco Malfoy attacked Harry, Ron and Hermione within the Room, Crabbe was slain by the resulting fire.