But it no longer suited its environment. In the age of the migrations the tribes had been broken, scattered, re-mixed. They had almost ceased to exist as important social entities. The social unit which had taken their place was the political community of men, of whatever tribe or tribes, who were held together in times of danger and constant war by means of a common circuit-wall, a Polis.[66:1] The idea of the tribe remained. In the earliest classical period we find every Greek city still nominally composed of tribes, but the tribes are fictitious. The early city-makers could still only conceive of society on a tribal basis. Every local or accidental congregation of people who wish to act together have to invent an imaginary common ancestor. The clash between the old tribal traditions that have lost their meaning, though not their sanctity, and the new duties imposed by the actual needs of the Polis, leads to many strange and interesting compromises. The famous constitution of Cleisthenes shows several. An old proverb expresses well the ordinary feeling on the subject: ὥς κε πόλις ῥέξειε, νόμος δ' ἀρχαῖος ἅριστος. 'Whatever the City may do; but the old custom is the best.' Now in the contest between city and tribe, the Olympian gods had one great negative advantage. They were not tribal or local, and all other gods were. They were by this time international, with no strong roots anywhere except where one of them could be identified with some native god; they were full of fame and beauty and prestige. They were ready to be made 'Poliouchoi', 'City-holders', of any particular city, still more ready to be 'Hellânioi', patrons of all Hellas. * * * * * In the working out of these three aims the Olympian religion achieved much: in all three it failed. The moral expurgation failed owing to the mere force of inertia possessed by old religious traditions and local cults. We must remember how weak any central government was in ancient civilization. The power and influence of a highly civilized society were apt to end a few miles outside its city wall. All through the backward parts of Greece obscene and cruel rites lingered on, the darker and worse the further they were removed from the full light of Hellenism.