The founder who prized a ready mind. Her diadem, made to sharpen wisdom, was stolen by her daughter Helena and hidden far from the castle. Centuries later Tom Riddle turned it into a Horcrux and stored it in the Room of Requirement. Helena, as the Grey Lady, is the one who tells Harry where it is.
Appears in
On the timeline
- c. 10th century
Hogwarts is founded
Hostility in Europe pushes Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw, and Salazar Slytherin to found a school and four houses. - Mid to late 1940s
Borgin and Burkes, and the search for the diadem
Tom works in the Knockturn Alley shop, hunts founder relics, and will turn Ravenclaw’s diadem into a Horcrux after a murder abroad. He does not become headmaster of anything. - Mid to late 1950s
Dumbledore refuses the Defence post
Tom returns, already changed, and asks again to teach Defence. Dumbledore refuses. On that visit the diadem Horcrux is hidden in the Room of Requirement.