The deliberate abstinence from sexual activity, usually in connection with a religious role or practice. It has existed in some form in most world religions. It may indicate a person's ritual purity (sexual relations being viewed as polluting) or may be adopted to facilitate spiritual advancement (as sexual activity would take place only within the bonds of matrimony, marriage and family were seen as an entangling distraction). In shamanistic religions, shamans are often celibate. In Hinduism, holy men (or women) who have left ordinary secular life to seek final liberation are celibate. Buddhism began as a celibate order, though many sects have since given up celibacy. Chinese taoism has monastics and independent celibate adepts. Islam has no institutional celibacy, but individuals may embrace it for personal spiritual advancement. Judaism has prescribed periods of abstinence, but long-term celibacy has not played a large role. The early Christian church tended to regard celibacy as superior to marriage. Since the 12th century it has been the rule for Roman Catholic clergy, though clerical celibacy was never adopted by Protestantism.