Origins of Modesty
"William James believed that modesty was not instinctive but acquired: women had found that generosity breeds contempt, and they had transmitted the findings to their daughters. Diderot went further back, and traced it to the jealousy of husbands, whose sense of ownership led them to enforce modesty upon their wives. In many tribes only the married women are clothed, their husbands (wiser than the creator of Penguin Isle) believing this to be an aid in the maintenance of property rights. When purchase replaced capture as the fashionable mode of marriage, and parents found that chaste daughters brought the highest price, they virtuously encouraged modesty."
Will Durant, The Pleasures of Philosophy