The origin of the application of the term pagan to polytheism is debated.[11] In the 19th century, paganism was adopted as a self-descriptor by members of various artistic groups inspired by the ancient world. In the 20th century, it came to be applied as a self-descriptor by practitioners of Modern Paganism, Neopagan movements and Polytheistic reconstructionists. Modern pagan traditions often incorporate beliefs or practices, such as nature worship, that are different from those in the largest world religions.[12][13]