in the Hindu (Hinduism) social system, members of the three upper varnas, or social classes—the Brahmans (priests and teachers), Kshatriya (warriors), and Vaishya (merchants)—whose sacrament of initiation is regarded as a second or spiritual birth. The initiation ceremony ( upanayana) invests the male caste members with a sacred thread, a loop worn next to the skin over the left shoulder and across the right hip. The lowest Hindu varna, the Sudra, and people whose status eludes the four-varna system altogether are regarded as theoretically ineligible to study or even to listen to the Vedas, a collection of hymns in archaic Sanskrit. However, a vital tradition of protest against this and similar ideas has long existed in India. The position of women in the dvija system is anomalous. Although clearly marked by caste, high-caste women are not considered eligible for Vedic study according to traditional canons. Since the 19th century, however, increasing numbers of such women have challenged the traditional view. They have become students of Sanskrit and Vedic subjects, notably in India's public institutions of higher learning, have chanted Vedic verses, and have even offered their services as specialists in Brahminical rituals.