The last remaining cause to be disposed of is the marriage of females--more especially of females married out of their own family or tribe. That much slavery was brought about in this way is provable in a variety of ways, and by the best traditional evidence. Homer’s “Iliad” abounds in testimonies to this effect. We have already cited the example of Cassandra, whom Othryon purchased from Priam, even as Jacob bought Leah and Rachel from their father Laban. Other passages are still more conclusive on the point. We find in the 9th book, for instance, that Agamemnon, regretting his having occasioned the wrath of Achilles, offers him, by way of appeasing it, certain costly presents; amongst others, seven Lesbian female slaves, along with Briseis; and, when Troy should be taken, twenty captives, the most beautiful, after Helen; and as a climax, one of his own three daughters--Achilles to choose, and to have her without purchase. And again, in the 16th book, we find Homer making mention of a certain Polydora, the mother of Menestheus, whom he describes as having been purchased for a wife, by her husband, at a great expense. The poems of Virgil contain similar evidences,--as for instance, when Juno proposes to Venus to settle their quarrels, and to accept Dido as a spouse and servant to her son Æneas. The term _service_ made use of by Virgil indicates clearly the servile relation to the husband which such marriages imposed upon women. Having explained the _origin_ of direct slavery, its legal establishment, and the principal known causes which multiplied it and consolidated it as a social institution, let us now inquire in what light it was regarded by the ancients themselves, wherefore it was able to maintain its footing all over the world, till the advent of Christianity; why it still obtains in so large a portion of the habitable globe; and why it has in nowise ceased, without giving birth to a masked or indirect slavery worse than itself. In this inquiry, our task will resolve itself in establishing the three following propositions:-- 1st. That direct or personal slavery was not regarded by the ancients in the light in which enlightened men of the present day regard it, that is to say, as an unnatural and inhuman institution, but, on the contrary, was considered to be a thing perfectly natural and reasonable in itself, and essential to the ends and purposes of society. 2nd. That the main cause of its permanence in the world was the universality of public opinion in its favour, rather than the force of law or custom; and that the slaves themselves fully participated in the general opinion.