Jethro Tull were a British rock group, formed in Luton, Bedfordshire, in December 1967. Initially playing blues rock, the band's sound soon incorporated elements of British folk music and hard rock to forge a progressive rock signature. The band was led by vocalist/flautist/guitarist Ian Anderson, and have included other significant members such as guitarist Martin Barre, keyboardist John Evan, drummers Clive Bunker, Doane Perry, and Barriemore Barlow, and bassists Glenn Cornick, Jeffrey Hammond, and Dave Pegg. The group achieved commercial success in 1969, with the folk-tinged blues album Stand Up, which reached No. 1 in the UK charts, and they toured regularly in the UK and the US. Their musical style shifted in the direction of progressive rock with the albums Aqualung, Thick as a Brick and A Passion Play, and shifted again to hard rock mixed with folk rock with Songs from the Wood and Heavy Horses. Jethro Tull have sold over 60 million albums worldwide, with 11 gold and five platinum albums among them. They have been described by Rolling Stone as "one of the most commercially successful and eccentric progressive rock bands". The last works released as a group were in 2003, though the band continued to tour until 2011. In April 2014, as he was concentrating on his solo career, Anderson said that Jethro Tull were finished.