The Rolling Stones are an English rock band formed in London in 1962. Active for over six decades, they are one of the most popular, influential, and enduring bands of the rock era. In the early 1960s, the band pioneered the gritty, rhythmically driven sound that came to define hard rock. Their first stable line-up consisted of vocalist Mick Jagger, guitarist Keith Richards, multi-instrumentalist Brian Jones, bassist Bill Wyman, and drummer Charlie Watts, after pianist Ian Stewart was side-lined by their manager Andrew Loog Oldham. During their early years, Jones was the primary leader. Oldham encouraged them to write their own songs. The Jagger–Richards partnership soon became the band's primary songwriting and creative force.