When books on Hinduism begin with a discussion of the Indus Valley civilization, one of the main postulates to illustrate the influence of the Indus upon Hinduism is that Śiva originates from this prehistoric civilization. The postulate is based on three types of objects found in the Mature Harappan context (c. 2500–1900 B.C.) which strongly evoke the personality of the great Hindu god. These objects are phallic emblems and baetyls, seals, and some sculptures. As to the first, conical shaped objects of stone, shell, faience, paste or clay were found in the Indus cities and an outpost, and these emblems are found to bear considerable resemblance to the later conventionalized Śivz-lingas. So too the Indus ring stones are likened to the later yonī-rings, objects representing the female organ and located at places holy to the Goddess (her pīṭhas). Regarding the second, a seal from Mohenjo-daro portraying a central figure with ithyphallic and tricephalic features, seated in yogic fashion and surrounded by four animals is identified as a proto-Śiva figure whose paśupati nature is already recognized. This famous seal, Mohenjo-daro seal No. 420, incorporates the most extensive range of symbols shared by a set of Indus seals, which are, on that account, all thought to exhibit proto-Śaivite symbolism. Lastly, two sculptures are suggestive evidence that the Indus region visualized something akin to the aspects that later comprise Śiva's nature. As such, a small, broken stone sculpture from Harappa is conjectured, when its missing limbs are reconstructed by modern scholarship, to assume a dancer's pose; in consequence the piece is understood as evocative of a Śiva Natarāja.