We have now traced in broad outline the extent of wife-purchase, and studied its general character and its principal forms. It appears essentially as a real contract of sale between third parties. Technically, at least, the bride and sometimes the bridegroom have nothing to do with the transaction. We have seen incidentally that the purchase-contract tends to become a ceremonial conveyance, and the bride-price to disappear in the dower. This transition is a fact of great social and legal import, and must therefore receive further attention. But, first, another question of interest arises: What is the place of wife-purchase in the evolution of human sexual relations? If it was not preceded by wife-capture as a general phase, is it the primitive method of contracting marriage? Or, to resolve the question into a more convenient form, what is the antiquity of mutual agreement as the basis of matrimonial union between a man and a woman? On its face, marriage by purchase appears as an institution which could arise only after considerable sociological and mental progress had been made. It implies relatively advanced ideas of property and social organization. Precisely the same is true, in a less degree, of wife-stealing, particularly of the systematic capture of women. It implies for one thing an appreciation of the economic value of woman's services which is wholly inconsistent with most primitive conditions. There are strong indications that in the beginning of distinctly human history marriage arose in the mutual consent of the parties. Nay, to discover the prototype of the primitive matrimonial contract it may be necessary to cross the boundary-line which separates man from the lower animals. This fact seems to have been too much neglected by writers on the history of marriage. Post, indeed, throws out a significant suggestion. Among very low races, he says, betrothal is a compact between the bride and the bridegroom. As soon, however, as the genealogical organization is further developed, marriage is changed from an individual relation to a relation between families, and the betrothal becomes a compact between the kindred groups. With the decay of the gentile constitution marriage and betrothal gradually become again an individual matter; so that in this regard the lowest and the highest stages of culture present the same phenomena.[645] [645] POST, _Familienrecht_, 158; _Afrikanische Jurisprudenz_, I, 377, 378, where will be found examples of peoples among whom free betrothal exists.