Therion (formerly Blitzkrieg and Megatherion) is a Swedish symphonic metal band founded by Christofer Johnsson in 1987. Its name was inspired by the Celtic Frost album "To Mega Therion". "To Mega Therion" is Greek for "The Great Beast" and was a title used by occultist Aleister Crowley. Originally a death metal band, Therion adjusted its musical style by adding orchestral elements, including choirs, classical musicians, and even a full orchestra at their concert performances. As a result, they are considered pioneers of the symphonic metal genre.