U.S. Protestant Groups. Christianity is a monotheistic religion founded by the followers of Jesus of Nazareth. Jesus, a Jew, was born in about 7 B.C. and assumed his public life, probably after his 30th year, in Galilee.The New Testament Gospels describe Jesus as a teacher and miracle worker.rotestantism. U.S. Protestant Groups. Christianity is a monotheistic religion founded by the followers of Jesus of Nazareth. Jesus, a Jew, was born in about 7 B.C. and assumed his public life, probably after his 30th year, in Galilee. The New Testament Gospels describe Jesus as a teacher and miracle worker.