Theater in South Asia is a complex phenomenon, for throughout the region the concept of performance, and hence the notion of theater, has been shaped by many different forces. To understand the resulting diverse theatrical developments, many quite unlike what developed in the West, one needs to refer not to the Greek philosopher Aristotle and his poetics but to Bharata and his Sanskrit treatise on music and drama, the Nāṭyaśāstra [see Theoretical Treatises], as well as to the enormous diversity of peoples and cultures of South Asia. These inhabitants include Mongoloid, Mediterranean, Negrito, and Proto-Austroloid peoples. Their languages fall into four distinct linguistic families—Indo-Iranian, Dravidian, Austro-Asiatic, and Sino-Tibetan—and their respective societies have developed in distinctive modes, such as the intricate web of the caste system, which operates irrespective of religion, race, or language. Among their religious practices, both major and minor world religions are represented, including Hinduism, Islam, Christianity, Sikhism, Buddhism, Jainism, and Judaism.