Among the nations of the East, the Egyptians, the Israelites, and the Greeks, and among those of the West, the Germans, early attained this stage of culture. Among all these races, at this stage of advancement, the esteem in which virginity, chastity, modesty, and sexual faithfulness are held is in marked contrast with other nations which offer the female of the house to the guest for his sexual enjoyment.[8] That this stage in the culture of sexual morality is quite high and makes its appearance much later than other developmental forms of culture—as, for example, æsthetics—is seen from the condition of the Japanese, with whom it is the custom to marry a woman only after she has lived for a year in the tea-houses (which correspond with European houses of prostitution), and to whom the nakedness of women is nothing shocking. At all events, among the Japanese every unmarried woman can prostitute herself without lessening her value as a future wife,—a proof that with this remarkable people woman possesses no ethical worth, but is valued in marriage only as a means of enjoyment, procreation, and work. Christianity gave the most powerful impulse to the moral elevation of the sexual relations by raising woman to social equality with man and elevating the bond of love between man and woman to a religio-moral institution.[9] The fact that in higher civilization human love must be monogamous and rest on a lasting contract was thus recognized. If nature does no more than provide for procreation, a commonwealth (family or state) cannot exist without a guaranty that the offspring shall flourish physically, morally, and intellectually. Christendom gained both mental and material superiority over the polygamous races, especially Islam, through the equalization of woman and man, and by establishing monogamous marriage and securing it by legal, religious, and moral ties. If Mohammed was actuated by a desire to raise woman from her place as a slave and means of sensual gratification to a higher social and matrimonial plane, nevertheless, in the Mohammedan world woman remained far below man, to whom alone divorce was allowed and also made very easy. Islam kept woman from any participation in public life under all circumstances, and thus hindered her intellectual and moral development. In consequence of this the Mohammedan woman has ever remained essentially a means of sensual gratification and procreation; while, on the other hand, the virtues and capabilities of the Christian woman, as housewife, educator of children, and equal companion of man, have been allowed to unfold in all their beauty. Islam, with its polygamy and harem-life, is glaringly contrasted with the monogamy and family life of the Christian world.