|"Is this all real? Or has this been happening inside my head?"
The subject of this article is a real-life person, group, company, product, or creative work that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really exists), and, as such, details contained in this article may differ from real world facts.
A harp is a stringed musical instrument with the plane of its strings positioned perpendicular to the soundboard. Harps can be enchanted to be played without assistance.
During the 1991–1992 school year at Hogwarts, a harp was used by Quirinus Quirrell to prevent the three-headed dog Fluffy from waking up while Quirrell attempted to steal the Philosopher's Stone for Lord Voldemort.