Although discussion of sign languages and the lives of deaf people is extremely rare in the history of South Asian literature, there are a few references to deaf people and gestural communication in texts dating from antiquity. Symbolic hand gestures known as mudras have been employed in religious contexts in Hinduism, Buddhism and Zoroastrianism for many centuries, although these religious traditions have often excluded deaf people from participation in a ritual or religious membership. In addition, classical Indian dance and theatre often employs stylised hand gestures with particular meanings.