released their first album in 1973, and were followed by bands like Aerosmith. Early heavy metal From the late 1960s the term heavy metal began to be used to describe some hard rock played with even more volume and intensity, first as an adjective and by the early 1970s as a noun. The term was first used in music in Steppenwolf's "Born to be Wild" (1967) and began to be associated with pioneer bands like Boston's Blue Cheer and Michigan's Grand Funk Railroad. By 1970 three key British bands had developed the characteristic sounds and styles which would help shape the subgenre. Led Zeppelin added elements of fantasy to their riff laden blues-rock, Deep Purple brought in symphonic and medieval interests from their progressive rock phrase and Black Sabbath introduced facets of the gothic and modal harmony, helping to produce a "darker" sound. These elements were taken up by a "second generation" of heavy metal bands into the late 1970s, including Kiss, Ted Nugent and Blue Öyster Cult from the US. Despite a lack of airplay and very little presence on the singles charts, late-1970s heavy metal built a considerable following, particularly among adolescent working-class males in North America and Europe. Christian rock Rock has been criticized by some Christian religious leaders, who have condemned it as immoral, anti-Christian and even demonic. However, Christian rock began to develop in the late 1960s, particularly out of the Jesus movement beginning in Southern California, and emerged as a subgenre in the 1970s with artists like Larry Norman, usually seen as the first major "star" of Christian rock. The genre has been particularly popular in the United States. Many Christian rock performers have ties to the contemporary Christian music scene, while other bands and artists are closely linked to independent music. Since the 1980s Christian rock performers have gained mainstream success, including figures such as the American gospel-to-pop crossover artist Amy Grant. 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. Punk and its aftermath (mid-1970s to the 1980s) Punk rock Punk rock was developed