"Bouree" by Jethro Tull is originally in the key of E minor. The song is an instrumental piece that was adapted by Jethro Tull from the "Bourrée in E minor" composed by Johann Sebastian Bach, which was originally written for the lute. Jethro Tull's version appears on their album "Stand Up," released in 1969. Ian Anderson, the frontman of Jethro Tull, arranged the piece for flute and guitar, giving it a unique folk-rock interpretation. The melody is characterized by intricate flute passages intertwined with lively guitar accompaniment, showcasing the band's virtuosity and blending of classical and rock elements.