Secondly, all the governments of the tribes were limited and constitutional, and all the governments of the city states with one possible exception, were absolute or unconstitutional. These propositions might almost be regarded as corollaries to those which preceded them, since in a mixed government the various elements impose limitations on the authority of one another, and ensure that each of them shall be subject to a constitution or general understanding about the exercise of power, while in an unmixed government the ruling person or class is likely to be subject to no restrictions: but it is more satisfactory to establish their truth from history. A moment's consideration shows that the mixed governments which prevailed in the tribes of the heroic age and at ancient Sparta, as well as those in which the military class were the ruling class, were all limited and constitutional. The unmixed governments of the cities were oligarchies, or tyrannies, or democracies. It is obvious that oligarchies and tyrannies were absolute governments, and in a democracy Aristotle tells us that the ruling class, the whole body of citizens, was above the law. The one possible exception occurs in the fully developed Athenian democracy, which was in many respects exceptional among Greek democracies. It is by no means clear that at Athens the mass of the citizens was an absolute ruler. The truth seems to be that it was an absolute ruler in so far that there were no limitations that it could not throw off at pleasure, but in practice it was very much like a constitutional ruler because it voluntarily submitted to formalities which restrained its actions. Thirdly, in the tribes, government was conducted for the good of the whole community; in the city states, except perhaps Athens, it was conducted for the good of the rulers. After all that has been said, these propositions require no further proving. We find then that in the tribes governments were mixed, constitutional and, in Aristotle's sense, normal; in the city states they were unmixed, and with one possible exception they were absolute and, in Aristotle's sense, abnormal or perverted. Now that we have discovered from observation of numerous instances that the governments of the Greek tribes and the governments of the Greek cities stood in strong contrast with one another, we may try to find out the causes to which the contrast was due.