Pythagoras imposed a strict rule of silence on his disciples; the Vestal virgins also were bound to severe silence for long years.
Religious orders such as the Benedictines have insisted on this as one of the essential rules of their institutes.
In monasteries of many orders there are specific places and times (usually at night) where speaking was more strictly prohibited. These places were termed "Regular Places" (church, refectory, dormitory etc.) and while the times were termed the "Great Silence". Outside of these places and times were accorded "recreations" allowing some conversation moderated by charity and moderation. Useless and idle words were universally forbidden. In active orders the members speak according to the needs of their various duties.
The Cistercian Order alone that admitted no relaxation from the strict rule of silence,[dubious – discuss] and the Reformed Cistercians maintain its severity (Trappists) though other contemplative Orders (Carthusians, Carmelites, Camaldolese etc.) are much more strict on this point than those engaged in active works.  In order to avoid speaking, many orders (Cistercians, Dominicans, Discalced Carmelites etc.) have a certain number of signs, by means of which the religious may have a limited communication with each other for the necessities that are unavoidable.
In the Indian religions religious silence is called Mauna and the name for a sage muni (see, for example Sakyamuni) literally means 'silent one'.