The roots of the Hindu caste system were already in place between 1000 and 1500 B.C., when the Aryans settled in the Indus River valley. The Rig Veda, a sacred text from the period, describes the four main castes (varnas) in traditional Hindu society: brahmins, the class of priests and teachers; kshatriyas, the warrior class, who were the rulers and soldiers; vaishyas, the commercial class of artisans, traders, and cultivators; and shudras, the servant and peasant class.
The Portuguese coined the word "caste" in the 16th century to refer to these four groups. To Hindus, however, the concept of caste has a narrower and more precise meaning, referring to the smaller subgroups defined by subtle distinctions of birth, intermarriage, and occupation. The four main castes comprise more than 2,000 subcastes.
Beneath these castes is a fifth population group—those without any caste, literally, outcastes. This includes the people traditionally known as "untouchables." The Indian constitution of 1950 made "untouchability" illegal. Today these people call themselves dalits ("oppressed"). Also in this fifth group are the "tribals," the 50 million Indians who live in tribal communities that predate the Aryan and Dravidian civilizations. They are members of the "backward" classes.
Caste is a religious and social institution of the Hindu peoples, who comprise about 80 percent of India's population. The rest of India is Muslim, Christian, Sikh, Buddhist, or Jain. Caste is such a deep-rooted and pervasive concept, however, that it has influenced Muslims, Christians, and Sikhs. For example, there are separate churches for dalit and non-dalit Christians. Even the tribals, who are not a part of Hindu society, have started observing "untouchability" toward dalits—who themselves have a caste hierarchy.
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