Domesticated Indian zebu cattle were present on the western margins of the South Asian subcontinent as early as 6000 B.C. Cattle were important in the agricultural economy of the Harappan civilization of the Indus Valley, but archaeological evidence suggests the bull was also assuming a symbolic or religious role in this culture during the third millennium B.C. There is, however, little to suggest that the cow was viewed as sacred. Following the decline of the Harappan civilization, northwestern India was settled by Aryan-speaking peoples who laid the foundations of modern Indian society. The Aryans were pastoral by nature and the economic importance of cattle to this society is mirrored in the role of cattle in ritual, in the pastoral symbolism of the Vedic literature (the ancient religious literature of Hinduism), and also in the association of the cow with various Vedic deities. Yet, again there is nothing to suggest the cow was viewed as sacred at this time. It is not until the appearance of the ahimsa philosophy at the end of the Vedic period, and the acceptance of this belief in the major religious philosophies of the region (Jainism, Buddhism, and later Hinduism), that the concept of the sanctity and inviolability of the cow began to crystallize. The ''sacred-cow concept'' appears as established doctrine in Hindu literature by the end of the medieval period (ca. fourth century A.D.), although popular practice appears to be at variance with this doctrine. A variety of historical, political, religious and social factors appear to have contributed to the general acceptance of the sacred cow doctrine by the Hindu population at large. During the 1960s, the ''sacred cow'' was at the center of a controversy in the social sciences concerning whether the concept was essentially religious in nature or reflected the ecological realities of the cattle economy of the Indian subcontinent. This debate notwithstanding, cattle remain central to the Indian economy, but also play a significant role in the religion and rituals of modern Hinduism, particularly those related to the worship of Krishna. Cattle have also assumed a political role in contemporary India, with anti-cow-slaughter legislation and the protection of the cow being identified with the emerging Hindutva movement. No understanding of South Asian culture can be complete without an awareness of the economic, historical, political and religious dimensions of cattle in the Indian subcontinent.