Wherever, therefore, the family relations exist, there is sure to exist also a wider society which by its authority gives to the powers exercised in those relations the character of rights. By what process the relations of husband and wife and the institution of the household may have come to be formed among descendants of a single pair, it is impossible to conceive or to discover, but in fact we find no trace in primitive history of households except as constituents of a clan recognising a common origin; and it is by the customs of the clan, founded on the conception of a common good, that those forbearances on the part of members of one household in dealing with another, which are necessary to the privacy of the several households, are secured. 239. The history of the development of family life is the history of the process _(a)_ by which family rights have come to be regarded as independent of the special custom of a clan and the special laws of a state, as rights which all men and women, as such, are entitled to. This, however, characterises the history of all rights alike. It is a history farther _(b)_ of the process by which the true nature of these rights has come to be recognised, as rights over persons; rights of which persons are the objects, and which therefore imply reciprocal claims on the part of those over whom they are exercised and of those who exercise them. The establishment of monogamy, the abolition of 'patria potestas' in its various forms, the 'emancipation of women' (in the proper sense of the phrase), are involved in these two processes. The principles (1) that all men and all women are entitled to marry and form households, (2) that within the household the claims of the husband and wife are throughout reciprocal, cannot be realised without carrying with them not merely monogamy, but the removal of those faulty relations between men and women which survive in countries where monogamy is established by law. 240. Under a system of polygamy, just so far as it is carried out, there must be men who are debarred from marrying. It can only exist, indeed, alongside of a slavery, which excludes masses of men from the right of forming a family. Nor does the wife, under a polygamous system, though she ostensibly marries, form a household, or become the co-ordinate head of a family, at all. The husband alone is head of the family and has authority over the children. The wife, indeed, who for the time is the favourite, may practically share the authority, but even she has no equal and assured position. The 'consortium omnis vitae,' the 'individua vitae consuetudo,' which according to the definition in the Digest is an essential element in marriage, is not hers. [1] [2]