Jethro Tull were a British rock group, formed in Luton, Bedfordshire, in December 1967, initially playing experimental blues rock, they later incorporated elements of classical music, folk music, jazz, hard rock and art rock into their music. Having more than 20 official members over the years, their music is characterised by the vocals, acoustic guitar, and flute playing of Ian Anderson, who led the band since its founding, and the guitar work of Martin Barre, who had been with the band since 1969, after he replaced original guitarist Mick Abrahams.
They achieved success early in 1969 with their UK No.1 album Stand Up, touring on both sides of the Atlantic and appearing in most of the festivals of 1969–70. But it was with the world-acclaimed album Aqualung (1971) that Jethro Tull established themselves in rock history. Together with Thick as a Brick (1972), the band conquered the annals of Progressive Rock . Two decades after their founding, the band earned the Grammy for Best Hard Rock/Metal Performance, Vocal or Instrumental for their Crest of a Knave (1987) album – which increased and sustained their fame through the years. Jethro Tull have sold over 60 million albums worldwide. They have been described by Rolling Stone as "one of the most commercially successful and eccentric progressive rock bands".