 Since the 1980s Christian rock performers have gained mainstream success, including figures such as the American gospel-to-pop crossover artist Amy Grant and the British singer Cliff Richard.While these artists were largely acceptable in Christian communities the adoption of heavy rock and glam metal styles by bands like Petra and Stryper, who achieved considerable mainstream success in the 1980s, was more controversial.From the 1990s there were increasing numbers of acts who attempted to avoid the Christian band label, preferring to be seen as groups who were also Christians, including P.O.D and Collective Soul.