Such was the ordinary policy of the best tyrants; and by these arts they were frequently able to reign in peace, and to transmit their power to their children. But the maxims and character of the tyranny generally underwent a change under their successors, and scarcely an instance was known of a tyrannical dynasty that lasted beyond the third generation. But, even where the tyrant did not make himself universally odious, or provoke the vengeance of individuals by his wantonness or cruelty, he was constantly threatened by dangers, both from within and from without, which it required the utmost vigour and prudence to avert. The party which his usurpation had supplanted, though depressed, was still powerful, more exasperated than humbled by its defeat, and ever ready to take advantage of any opportunity of overthrowing him, either by private conspiracy, or by affecting to make common cause with the lower classes, or by calling in foreign aid. And in Greece itself such aid was always at hand: the tyrants indeed were partially leagued together for mutual support. But Sparta threw all her might into the opposite scale. She not only dreaded the contagion of an example which might endanger her own institutions, but was glad to extend her influence by taking an active part in revolutions, which would cause the states restored, by her intervention, to their old government to look up to her with gratitude and dependence as their natural protectress. And accordingly Thucydides ascribes the overthrow of most of the tyrannies which flourished in Greece before the Persian War to the exertions of Sparta. The immediate effect produced by the fall of the tyrants depended on the hands by which it was accomplished. Where it was the work of Sparta, she would aim at introducing a constitution most in conformity to her own. But the example of Athens will show, that she was sometimes instrumental in promoting the triumph of principles more adverse to her views than those of the tyranny itself. When, however, the struggle which had been interrupted by the temporary usurpation was revived, the parties were no longer in exactly the same posture as at its outset. In general the commonalty was found to have gained, in strength and spirit, even more than the oligarchy had lost; and the prevalent leaning of the ensuing period was on the side of democracy. Indeed the decisive step was that by which the oligarchy of wealth was substituted for the oligarchy of birth. This opened the door for all the subsequent innovations, by which the scale of the timocracy was gradually lowered, until it was wholly abolished. DEMOCRACIES