The Rolling Stones are an English rock band formed in London in 1962. Active across seven decades, they are one of the most popular 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. During their early years, Jones was the primary leader of the band. After Andrew Loog Oldham became the group's manager in 1963, he encouraged them to write their own songs. The Jagger–Richards partnership became the band's primary songwriting and creative force.