There are several different sociological definitions and descriptions for the term. Among the first to define them were Max Weber and Ernst Troeltsch (1912). In the church-sect typology they are described as newly formed religious groups that form to protest elements of their parent religion (generally a denomination). Their motivation tends to be situated in accusations of apostasy or heresy in the parent denomination; they are often decrying liberal trends in denominational development and advocating a return to true religion. The American sociologists Rodney Stark and William Sims Bainbridge assert that "sects claim to be authentic purged, refurbished version of the faith from which they split". They further assert that sects have, in contrast to churches, a high degree of tension with the surrounding society. Other sociologists of religion such as Fred Kniss have asserted that sectarianism is best described with regard to what a sect is in tension with. Some religious groups exist in tension only with co-religious groups of different ethnicities, or exist in tension with the whole of society rather than the church which the sect originated from.