During several centuries succeeding the period of the supposed Trojan war, a gradual change occurred in the political history of the Grecian states, the results of which were an abandonment of much of the kingly authority that prevailed through the Heroic Age. At a still later period this change was followed by the introduction and establishment, at first, of aristocracies, and, finally, of democratic forms of government; which latter decided the whole future character of the public life of the Grecians. The three causes, more prominent than the rest, that are assigned by most writers for these changes, and the final adoption of democratic forms, are, first, the more enlarged views occasioned by the Trojan war, and the dissensions which followed the return of those engaged in it; second, the great convulsions that attended the Thessalian, Bœotian, and Dorian migrations; and, third, the free principles which intercourse and trade with the Grecian colonies naturally engendered. But of these causes the third tended, more than any other one, to change the political condition of the Grecians. Whether the migrations of the Greek colonists were occasioned, as they generally were, by conquests that drove so many from their homes to seek an asylum in foreign lands, or were undertaken, as was the case in some instances, with the consent and encouragement of the parent states, there was seldom any feeling of dependence on the one side, and little or no claim of authority on the other. This was especially the case with the Ionians, who had scarcely established themselves in Asia Minor when they shook off the authority of the princes who conducted them to their new settlements, and established a form of government more democratic than any which then existed in Greece. With the rapid progress of mercantile industry and maritime discovery, on which the prosperity of the colonies depended, a spirit of independence grew up, which erelong exerted an influence on the parent states of Greece, and encouraged the growth of free principles there. "Freedom," says an eloquent author,[Footnote: Heeren, "Polities of Ancient Greece," p. 103.] "ripens in colonies. Ancient usage cannot be preserved, cannot altogether be renewed, as at home. The former bonds of attachment to the soil, and ancient customs, are broken by the voyage; the spirit feels itself to be more free in the new country; new strength is required for the necessary exertions; and those exertions are animated by success. When every man lives by the labor of his hands, equality arises, even if it did not exist before. Each day is fraught with new experience; the necessity of common defence is more felt in lands where the new settlers find ancient inhabitants desirous of being free from them. Need we wonder, then, if the authority of the founders of the Grecian colonies, even where it had originally existed, soon gave way to liberty?"