One principal cause of the republican forms of government that began (as, after the Dorian migration, the different tribes became settled in those seats by which they are historically known) to spread throughout Greece, was, therefore, the establishment of colonies retaining constant intercourse with the parent states. A second cause is to be found in the elements of the previous constitutions of the Grecian states themselves, and the political principles which existed universally, even in the heroic ages: so that, in fact, the change from monarchy to republicanism was much less violent than at the first glance it would seem to our modern notions. The ancient kings, as described by Homer, possessed but a limited authority, like that of the Spartan kings - extensive in war, narrow in peace. It was evidently considered that the source of their authority was in the people. No notion seems to have been more universal among the Greeks than that it was for the community that all power was to be exercised. In Homer's time popular assemblies existed, and claimed the right of conferring privileges on rank. The nobles were ever jealous of the prerogative of the prince, and ever encroaching on his accidental weakness. In his sickness, his age, or his absence, the power of the state seems to have been wrested from his hands - the prey of the chiefs, or the dispute of contending factions. Nor was there in Greece that chivalric fealty to a person which characterizes the North. From the earliest times it was not the MONARCH, that called forth the virtue of devotion, and inspired the enthusiasm of loyalty. Thus, in the limited prerogative of royalty, in the jealousy of the chiefs, in the right of popular assemblies, and, above all, in the silent and unconscious spirit of political theory, we may recognise in the early monarchies of Greece the germes of their inevitable dissolution. Another cause was in that singular separation of tribes, speaking a common language, and belonging to a common race, which characterized the Greeks. Instead of overrunning a territory in one vast irruption, each section seized a small district, built a city, and formed an independent people. Thus, in fact, the Hellenic governments were not those of a country, but of a town; and the words "state" and "city" were synonymous . Municipal constitutions, in their very nature, are ever more or less republican; and, as in the Italian states, the corporation had only to shake off some power unconnected with, or hostile to it, to rise into a republic. To this it may be added, that the true republican spirit is more easily established among mountain tribes imperfectly civilized, and yet fresh from the wildness of the natural life, than among old states, where luxury leaves indeed the desire, but has enervated the power of liberty, "as the marble from the quarry may be more readily wrought into the statue, than that on which the hand of the workman has already been employed." 
III. If the change from monarchy to republicanism was not very violent in itself, it appears to have been yet more smoothed away by gradual preparations. Monarchy was not abolished, it declined. The direct line was broken, or some other excuse occurred for exchanging an hereditary for an elective monarchy; then the period of power became shortened, and from monarchy for life it was monarchy only for a certain number of years: in most cases the name too (and how much is there in names!) was changed, and the title of ruler or magistrate substituted for that of king.
Thus, by no sudden leap of mind, by no vehement and short-lived revolutions, but gradually, insensibly, and permanently, monarchy ceased - a fashion, as it were, worn out and obsolete - and republicanism succeeded. But this republicanism at first was probably in no instance purely democratic. It was the chiefs who were the visible agents in the encroachments on the monarchic power - it was an aristocracy that succeeded monarchy. Sometimes this aristocracy was exceedingly limited in number, or the governing power was usurped by a particular faction or pre-eminent families; then it was called an OLIGARCHY. And this form of aristocracy appears generally to have been the most immediate successor to royalty. "The first polity," says Aristotle , "that was established in Greece after the lapse of monarchies, was that of the members of the military class, and those wholly horsemen," . . . . . "such republics, though called democracies, had a strong tendency to oligarchy, and even to royalty."  But the spirit of change still progressed: whether they were few or many, the aristocratic governors could not fail to open the door to further innovations. For, if many, they were subjected to dissensions among themselves - if few, they created odium in all who were excluded from power. Thus fell the oligarchies of Marseilles, Ister, and Heraclea. In the one case they were weakened by their own jealousies, in the other by the jealousies of their rivals. The progress of civilization and the growing habits of commerce gradually introduced a medium between the populace and the chiefs. The MIDDLE CLASS slowly rose, and with it rose the desire of extended liberties and equal laws.