He sought evidence for this hypothesis in the scheme of tribal organization of Rome. The primitive city was divided into three tribes, thirty curiae and, as he believed, three hundred gentes. As no one could be a citizen without membership in a gens,[145] and as the patricians alone were active members of the gentes,[146] it must follow that the patricians alone were citizens. It is doubtful whether he would have proposed this hypothesis had it not been for the analogy of the Attic tribal scheme. An imperfect quotation from the lost part of Aristotle’s _Constitution of Athens_[147] seems to signify that the Athenian state was once divided into four tribes (φυλαί), twelve phratries and three hundred and sixty gentes (γένη). On this authority Niebuhr supposes that the phratry was a group of gentes, and he assumes further that both phratries and gentes were composed exclusively of eupatrids.[148] But the suppositions (1) that there were three hundred and sixty gentes, (2) that the phratry was a group of gentes, (3) that both phratries and gentes contained only eupatrids are contradicted by well known facts. From the earliest times the Greek tribes and phratries included commons as well as nobles. This is true of the Homeric Greeks,[149] and a law of Draco[150] proves that the early Attic phratry comprised both nobles and commons. In historical times all citizens belonged to the phratries; whereas but few were members of the gentes.[151] Most of the gentes were in fact composed of the old landed nobility, though a few, like the Chalkidae and the Eupyridae, were apparently industrial guilds, which had received the privileges of the gentes. So far therefore from supporting Niebuhr in his peculiar view of the Roman gentes and curiae, the Attic analogy militates in every way against him. As his assumption that the curia was a group of ten gentes has already been disproved,[152] it remains only to consider whether the gens was an exclusively patrician institution. From the circumstance that patricianism is not given as an element of Scaevola’s definition, quoted by Cicero,[153] we may at once conclude that in their time plebeians, too, were gentiles. This conclusion is supported by a variety of evidence.