Engels retraces woman’s history from this point of view in The Origin of the Family; to him, this history depends essentially on the history of technology. In the Stone Age, when the land belonged to all members of the clan, the rudimentary nature of the primitive spade and hoe limited agricultural possibilities: feminine strength was at the level of work needed for gardening. In this primitive division of labor, the two sexes already constitute two classes in a way; there is equality between these classes; while the man hunts and fishes, the woman stays at home; but the domestic tasks include productive work: pottery making, weaving, gardening; and in this way, she has an important role in economic life. With the discovery of copper, tin, bronze, and iron, and with the advent of the plow, agriculture expands its reach: intensive labor is necessary to clear the forests and cultivate the fields. So man has recourse to the service of other men, reducing them to slavery. Private property appears: master of slaves and land, man also becomes the proprietor of the woman. This is the “great historical defeat of the female sex.” It is explained by the disruption of the division of labor brought about by the invention of new tools. “The same cause that had assured woman her previous authority in the home, her restriction to housework, this same cause now assured the domination of the man; domestic work thence faded in importance next to man’s productive work; the latter was everything, the former an insignificant addition.” So paternal right replaces maternal right: transmission of property is from father to son and no longer from woman to her clan. This is the advent of the patriarchal family founded on private property. In such a family woman is oppressed. Man reigning sovereign permits himself, among other things, his sexual whims: he sleeps with slaves or courtesans, he is polygamous. As soon as customs make reciprocity possible, woman takes revenge through infidelity: adultery becomes a natural part of marriage. This is the only defense woman has against the domestic slavery she is bound to: her social oppression is the consequence of her economic oppression. Equality can only be reestablished when both sexes have equal legal rights; but this enfranchisement demands that the whole of the feminine sex enter public industry. "Woman cannot be emancipated unless she takes part in production on a large social scale and is only incidentally bound to domestic work. And this has become possible only within a large modern industry that not only accepts women’s work on a grand scale but formally requires it."
—Simone de Beauvoir, The Second Sex, p. -1