Pollux—probably from Aristotle’s lost work on the Constitutions of Greece—informs us, distinctly, that the members of the same gens at Athens were not commonly related by blood,—and even without any express testimony we might have concluded such to be fact: to what extent the gens, at the unknown epoch of its first formation, was based upon actual relationship, we have no means of determining, either with regard to the Athenian or the Roman gentes, which were in all main points analogous. Gentilism is a tie by itself; distinct from the family ties, but presupposing their existence and extending them by an artificial analogy, partly founded on religious belief and partly on positive compact, so as to comprehend strangers in blood. All the members of one gens, or even of one phratry, believed themselves to be sprung, not, indeed, from the same grandfather or greatgrandfather, but from the same divine or heroic ancestor: all the contemporary members of the phratry of Hekatæus had a common god for their ancestor in the sixteenth degree; and this fundamental belief, into which the Greek mind passed with so much facility, was adopted and converted by positive compact into the gentile and phratric principle of union. It is because such a transfusion, not recognized by Christianity, is at variance with modern habits of thought, and because we do not readily understand how such a legal and religious fiction can have sunk deep into the Greek feelings, that the phratries and gentes appear to us mysterious: but they are in harmony with all the legendary genealogies which have been set forth in the preceding volume. Doubtless Niebuhr, in his valuable discussion of the ancient Roman gentes, is right in supposing that they were not real families, procreated from any common historical ancestor: but it is not the less true, though he seems to suppose otherwise, that the idea of the gens involved _the belief_ in a common first father, divine or heroic,—a genealogy which we may properly call fabulous, but which was consecrated and accredited among the members of the gens itself, and served as one important bond of union between them.[91] And though an analytical mind like Aristotle might discern the difference between the gens and the family, so as to distinguish the former as the offspring of some special compact, still, this is no fair test of the feelings usual among early Greeks; nor is it certain that Aristotle himself, son of the physician Nikomachus, who belonged to the gens of the Asklepiads,[92] would have consented to disallow the procreative origin of _all_ these religious families without any exception. The natural families of course changed from generation to generation, some extending themselves while others diminished or died out; but the gens received no alterations, except through the procreation, extinction, or subdivision of these component families; accordingly, the relations of the families with the gens were in perpetual course