But these unions, though incestuous for us, have not been practised amongst savages and inferior races only. According to Strabo, the ancient Irish married, without distinction, their mothers and sisters.[146] We are told by Justin and Tertullian[147] that the Parthians and Persians married their own mothers without scruple. In ancient Persia, religion went so far even as to sanctify the union of a son with his mother.[148] Priscus relates that these marriages were also permitted among the Tartars and Scythians, and it is reported, too, that Attila married his daughter Esca.[149] Whether from a survival of ancient morals, or the care to preserve purity of race, conjugal unions between brother and sister were authorised, or even prescribed, in various countries, for the royal families. The kings of ancient Egypt were obliged to marry their sisters, and Cleopatra thus became the wife of her brother Ptolemy Dionysius. The Incas of Peru were subject to a similar law; and at Siam also, when the traveller La Loubère visited it, the king had married his sister.[150] But I shall have to return to the subject of marriage between relations in treating of the endogamic _régime_ which has been, or is, in force among many peoples. These incestuous marriages astonish us, and certain of them are even revolting to our ideas, as, for example, the union of the mother with the son. Another custom will probably surprise, if not shock us quite as much. I allude to experimental marriages, which are far from being rare. They will appear, however, less singular, if we remember that in societies of low order little value is set on the chastity of young girls; virginal purity is not at all prized, and there are even some peoples, as the Saccalaves of Madagascar,[151] for instance, and also certain indigenous peoples of India,[152] among whom it is regarded as a duty for the mothers themselves to deflower their daughters before marrying them. With such morals prevailing, experimental marriages seem natural enough. De Champlain, an ancient French traveller in North America, relates that the Redskins of Canada always lived a few days together, and then quitted each other if the trial had not been satisfactory to either of them.[153] A Spanish chronicler, Herrara, reports that the Otomies of Mexico spent a night of trial with the woman that they desired to marry; they could quit her afterwards, but only on condition of not retaining her during the following day.[154]