What happened in the case of one father of a family would as naturally happen in respect of others. In the progress of time, some of the younger branches would naturally stray from the paternal home, and emigrate to other lands, where they would settle down and, in time, become the heads of families--the founders of new races of slaves. Indeed, we have but to imagine the case of one to apply to thousands similarly circumstanced, and we shall see the origin of human slavery at once satisfactorily explained. Those early fathers, or heads of families, would naturally love some of their children better than others; at least, they would have more confidence in some one than in the rest. To those so loved, or so favoured, would naturally devolve the headship of the family, or such portions of the patrimonial estate as might enable them to found new families elsewhere. These families, like the parent one, would as naturally resolve themselves into little communities of masters and slaves; so that in course of time, by the natural operation of one and the same first cause, the whole of society would find itself, what we find it to have been in all early history, an aggregation of souls divided everywhere into two great classes--a master-class possessing, and a slave-class possessed. Let us not imagine, however, that a social order which appears to us so inhuman and so unnatural was viewed in this light, or inspired _our_ feelings, in the ancient world; it would be a great mistake to suppose this. Nothing was further from the contemplation of the men of antiquity than our notions and theories about the equality of human rights. The idea of what man ought to be, or is capable of being made, was an idea unknown to the ancient world. The division of the human race into masters and slaves appeared to them a perfectly natural division: they saw no other; they never heard of any other; they appear never to have conceived the possibility of any other. Even the slaves themselves never complained of slavery _as an institution_; they never demanded liberty in the sense we demand it. When they did complain, it was not because they thought that one class ought not to be a master-class and the other a slave-class: that was an idea quite beyond them. When they complained--and they often _did_ complain, and sometimes rebel too--it was either because they found their masters harsh and cruel, and wished to exchange them for new and better ones, or because they hoped, by breaking their fetters and becoming soldiers, pirates, or adventurers of some kind, to exchange their condition as slaves for the more enviable one of slave-owners. History records several insurrections of slaves that took place in ancient times; but in no one instance does it appear that the insurgents took up arms for the principle of equality, or for any cause common to other slaves as well as to themselves. Of this fact we shall adduce some notable evidences in the progress of this inquiry.