While we're on the subject of young musical prodigies, I'd like to shine a light on the influential metal band Windir. At age 16, Terje Bakken wrote, arranged, and performed everything on the first album (with the exception of drums): Vocals, Guitars, Bass, Keyboards, and Accordion.

His second album, Arntor, also a solo work, was released 2 years later, and is considered one of the best albums ever of the genre. At age 18.