Christian/Gospel music is the sound of the devout channeling their faith into song. While requiems, hymns, and gospel have long been performed in places of worship, popular music also has a tradition of religious acts taking their message to secular venues. Gospel vocal groups such as the Soul Stirrers toured nationally from the late-1920s through the '60s, spreading the Word to Beatles-worthy squeals from adoring young fans. The lure of greater exposure (and, sometimes, more money) tempted many such singers to jump into the straight pop marketplace (Sam Cooke did just that), but there were always others to fill the gap. The Mighty Clouds of Joy kept the tradition going in the '70s, changing the classic sound of a gospel quartet just enough to score a Disco hit along the way. As Gospel pared down from choirs to vocal groups to individual artists, religious musicians who didn't incorporate choirs into their music or performed their material in contemporary musical styles became known as Christian artists. The '70s and '80s saw Christian acts with little or no Gospel overtones become a legitimate force in the music industry, and various subgenres have, from time to time, experienced brief flurries of devotional acts, from the heaven's Metal of Stryper in the '80s to the Pearl Jam-esque Alternative Christian popularized by Jars of Clay in the '90s. (Country music, meanwhile, always seems to flip back and forth between sinning on Saturday night and praising the Lord on Sunday morning.) Today, there are many sub-styles of Christian music, all bearing the same fundamental message of encouragement in musical form.