LONDON (Dec. 23) - Joe Strummer, frontman with the Clash whose 1979 track "London Calling" exploded as one of punk's biggest anthems, has died at the age of 50, a spokesman said on Monday. The singer, guitarist and songwriter died on Sunday at his home in Somerset, western England of unknown causes. "We do not yet know the cause of death, but we believe it was not suspicious and that he passed away peacefully. An autopsy will be forthcoming," the spokesman said. Born John Graham Mellor in Ankara, Turkey, Strummer's talents propelled him from busking on the London Underground to fame with the Clash, who with the Sex Pistols defined the in-your-face sound and style of 1970s British punk. Until they split in the 1980s, the Clash produced a catalog of punk classics, including "Career Opportunities" and "Should I Stay or Should I Go?," distilling the depression, anger and energy of 1970s Britain. But they transcended the three-chord aggression to deliver messages of anti-racism and social consciousness. Strummer, the son of a British diplomat, wrote many of their biggest hits. "He was one of the most important figures in modern British music, a powerful performer and wordsmith on a level with Bob Dylan," said Pat Gilbert, editor of British music magazine Mojo "His music had compassion and vision, backed with an agenda to change the world for the better," he told Reuters. Sometimes described as rebels with a cause, the Clash fused a variety of musical styles -- reggae, funk and even rap -- with a political message that brought punk to the mainstream and also found big success in the U.S. market. Bono, lead singer from the Irish band U2, said: "The Clash was the greatest rock band. They wrote the rule book for U2." DEFINITIVE PUNK In 1976, Strummer met a then 23-year-old guitarist Mick Jones and linked up with bassist Paul Simonon and drummer Terry Chimes. As the Clash, the quartet made an immediate and explosive impact in Britain. Rolling Stone magazine called their 1977 eponymous debut "The definitive punk album." Follow-ups "Give 'Em Enough Rope" (1978), and "London Calling" (1979) also became instant punk classics. After The Clash split, a tireless Strummer stayed center stage with a variety of projects, dabbling in acting and writing music for films. More recently, Strummer toured with a new band, the Mescaleros, and played a benefit concert with Mick Jones in November, reuniting with his partner in punk for the first time in nearly 20 years. At the time of his death, Strummer was collaborating with U2's Bono and Dave Stewart, formerly of the Eurythmics, on an AIDS awareness track. "The Clash are to be inducted into the Rock and Roll Hall of Fame next year and there was hope that there would be a reunion and a tour...this must be especially sad for their fans," Gilbert said. Strummer's death was a double blow for punk fans still mourning the fatal drug overdose in June of singer Dee Dee Ramone from legendary American band the Ramones. Strummer is survived by his wife, two daughters and one stepdaughter.