It is apparently from the differences in civilization and political power resulting from these successive strata of conquerors over the conquered that the Hindu system of caste arose. A caste is defined in the census report of 1901 as a collection of families or groups of families bearing a common name, which usually denotes or is associated with a specific occupation; claiming common descent from a mythical ancestor, human or divine, professing to follow the same calling, and regarded by those who are competent to give an opinion as forming a single homogeneous community. A caste is almost invariably endogamous, in the sense that a member of the large circle denoted by the common name may not marry outside that circle, but within the circle there are usually a number of smaller circles, each of which is also endogamous. Thus it is not enough to say at the present day that a Brahman cannot marry any woman who is not a Brahman; his wife must not only be a Brahman, but must also belong to the same endogamous division of the Brahman caste. The origin of caste was described by Sir Denzil Ibbetson in the Punjab Census Report of 1881 in the following terms: "We have the following steps in the process by which caste has been evolved in the Punjab--(1) the tribal divisions common to all primitive societies; (2) the gilds based upon hereditary occupation common to the middle life of all communities; (3) the exaltation of the priestly office to a degree unexampled in other countries; (4) the exaltation of the Levitical blood by a special insistence upon the necessarily hereditary nature of occupation; (5) the preservation and support of this principle by the elaboration from the theories of the Hindu creed or cosmogony of a purely artificial set of rules regulating marriage and intermarriage, declaring certain occupations and foods to be impure and polluting, and prescribing the conditions and degree of social intercourse permitted between the several castes. Add to these the pride of social rank and the pride of blood, which are natural to man, and which alone could reconcile a nation to restrictions at once irksome from a domestic and burdensome from a material point of view, and it is hardly to be wondered at that caste should have assumed the rigidity which distinguishes it in India." Caste has, in fact, come to be the chief dominating factor in the life of the ordinary native of India. All a man's actions from the cradle to the grave are regulated by it; and the tendency in modern India is for tribes to turn into castes. So widespread is its influence that, though originally a purely Hindu institution, it has come to exercise considerable influence over their Mahommedan neighbours (see CASTE). [Illustration: Map of India (Southern part). Scale 1:7,500,000] Religion.