The enterprises of the heroic age, as we see from the example of the Trojan War itself, often led to the extinction, or expulsion, of a royal family, or of its principal members; and no principle appears to have been generally recognised which rendered it necessary, in such cases, to fill a vacant throne or to establish a new dynasty, while every such calamity inevitably weakened the authority of the kings, and made them more dependent on the nobles, who, as an order, were not affected by any disasters to individuals. But the great convulsions which attended the Thessalian, Bœotian, and Dorian migrations, contributed still more effectually to the same end. In most parts of Greece they destroyed or dislodged the line of the ancient kings, who, when they were able to seek new seats, left behind them the treasures and the strongholds which formed the main supports of their power: and, though the conquerors were generally accustomed to a kingly government, it must commonly have lost something of its vigour when transplanted to a new country, where it was subject to new conditions, and where the prince was constantly reminded, by new dangers, of the obligations which he owed to his companions in arms. Yet, even this must be considered rather as the occasion which led to the abolition of the heroic monarchy, than as the cause: that undoubtedly lay much deeper, and is to be sought in the character of the people—in that same energy and versatility which prevented it from ever stiffening, even in its infancy, in the mould of oriental institutions, and from stopping short, in any career which it had once opened, before it had passed through every stage.
It seems to have been seldom, if ever, that royalty was abolished by a sudden and violent revolution; the title often long survived the substance, and this was extinguished only by slow successive steps. These consisted in dividing it among several persons, in destroying its inheritable quality, and making it elective, first in one family, then in more; first for life, then for a certain term; in separating its functions, and distributing them into several hands. In the course of these changes it became more and more responsible to the nobles, and frequently, at a very early stage, the name itself was exchanged for one simply equivalent to ruler, or chief magistrate. The form of government which thus ensued might, with equal propriety, be termed either aristocracy or oligarchy, but, in the use of the terms to which these correspond, the Greek political writers made a distinction, which may at first sight appear more arbitrary than it really is. They taught—not a very recondite truth—that the three forms of government, that of one, that of a few, and that of the many, are all alike right and good, so long as they are rightly administered, with a view, that is, to the welfare of the state, and not to the interest of an individual or of a particular class. But, when any of the three loses sight of its legitimate object, it degenerates into a vicious species, which requires to be marked by a peculiar name. Thus a monarchy, in which selfish aims predominate becomes a tyranny. The government of a few, conducted on like principles, is properly called an oligarchy. But to constitute an aristocracy, it is not sufficient that the ruling few should be animated by a desire to promote the public good: they must also be distinguished by a certain character; for aristocracy signifies the rule of the best men.
More distinctly to understand the peculiar nature of the Greek oligarchies, it is necessary to consider the variety of circumstances under which they arose. By the migrations which took place in the century following the Trojan War, most parts of Greece were occupied by a new race of conquerors. Everywhere their first object was to secure a large portion of the conquered land; but the footing on which they placed themselves, with regard to the ancient inhabitants, was not everywhere the same; it varied according to the temper of the invaders, or of their chiefs, to their relative strength, means, and opportunities. In Sparta, and in most of the Dorian states, the invaders shunned all intermixture with the conquered, and deprived them, if not of personal freedom, of all political rights. But elsewhere, as in Elis, and probably in Bœotia, no such distinction appears to have been made; the old and the new people gradually melted into one.