We have seen that in post-Homeric times the long submerged group-system of tribal society resumed its sway. Though the wars and migrations of the period must for a time have weakened its power, yet ultimately, as Thucydides says, ‘Hellas recovered tranquillity, and began to send out colonies.’[41] The new doctrine of Apollo, which regarded homicide as a ‘pollution,’ was, we think, adopted about the seventh century, which was pre-eminently the period of Greek colonisation. Henceforth the homicide was conceived as an enemy not merely of the ghosts of those whom he had slain but also of the gods of the new States which had evolved out of chaos through synoekism. But Attica, almost alone of all Greek States, was immune from the chaos of migrations and invasions and retained for the most part its original inhabitants. Therefore Attica, more than any other Greek State, required, for its political unification, a more strenuous law-making, a more violent attack on the civic action of the clan. Yet we cannot suppose that the clans and tribes of the group-system were destroyed in Attica any more than they were in other parts of Greece. All through the historical era clans and tribes continued to exercise limited powers and jurisdictions; the old ties of kindred and of neighbourhood were maintained under the form of religious corporations long after the group-system had lost its political power. All this is merely to say that the old aristocracy of birth was replaced by plutocracy and democracy. The various stages in this transition will be made clear if we give a brief sketch of the political evolution of Attica, a sketch which is all the more necessary because of the analysis which we shall have to give, at a later stage, of blood-vengeance in Attic tragedy. EVOLUTION OF THE ATTIC STATE We need not allow ourselves to be detained by the obscure and conflicting legends which centre round the birth of the Attic nation. Coulanges[42] refers to the traditions concerning local kings of Attica before the time of Cecrops. Pausanias refers to a kind of religious amalgamation which was doubtless the concomitant of political synoekism: ‘Sacred to Athene,’ he says, ‘is all the rest’[43] of Athens and similarly all Attica; although they worship different gods in different townships, none the less do they honour Athene generally. He points out that four villages at Marathon were still in his time united in a local worship of Apollo, and that legend attributed to Cecrops a federation of Attica into twelve different states.[44] While Coulanges accepts the legend which attributes to Theseus the political unification of Attica, he thinks[45] that Plutarch[46] and Thucydides[47] are in error in supposing that Theseus abolished the local prytanies and magistracies. ‘If he attempted this,’ he says, ‘he certainly did not succeed; for a long while after him we still find the local worships, the assemblies, and the kings of the tribes.’