Industrial expansion, money, usury, private land, and mortgage thus progressed with the concentration and centralization of wealth in the hands of a small class, accompanied by the increasing impoverishment of the masses and the increasing mass of paupers. The new aristocracy of wealth, so far as it did not coincide with the old tribal nobility, forced the latter permanently into the background (in Athens, in Rome, among the Germans). And this division of free men into classes according to their wealth was accompanied, especially in Greece, by an enormous increase in the number of slaves[38] whose forced labor formed the basis on which the whole superstructure of society was reared. Let us now see what became of the gentile constitution through this revolution of society. Gentilism stood powerless in the face of the new elements that had grown without its assistance. It was dependent on the condition that the members of a gens, or of a tribe, should live together in the same territory and be its exclusive inhabitants. That had long ceased to be the case. Gentes and tribes were everywhere hopelessly intermingled, slaves, clients, and foreigners lived among citizens. The capacity for settling down permanently which had only been acquired near the end of the middle stage of barbarism, was time and again sidetracked by the necessity of changing the abode according to the dictates of commerce, different occupations and the transfer of land. The members of the gentile organizations could no longer meet for the purpose of taking care of their common interests. Only matters of little importance, such as religious festivals, were still observed in an indifferent way. Beside the wants and interests for the care of which the gentile organs were appointed and fitted, new wants and interests had arisen from the revolution of the conditions of existence and the resulting change in social classification. These new wants and interests were not only alien to the old gentile order, but thwarted it in every way. The interests of the craftsmen created by division of labor, and the special necessities of a town differing from those of the country, required new organs. But every one of these groups was composed of people from different gentes, phratries, and tribes; they included even strangers. Hence the new organs necessarily had to form outside of the gentile constitution. But by the side of it meant against it. And again, in every gentile organization the conflict of interests made itself felt and reached its climax by combining rich and poor, usurers and debtors, in the same gens and tribe. There was furthermore the mass of inhabitants who were strangers to the gentiles. These strangers could become very powerful, as in Rome, and they were too numerous to be gradually absorbed by the gentes and tribes. The gentiles confronted these masses as a compact body of privileged individuals. What had once been a natural democracy, had been transformed into an odious