At the side of the centralising Emperor appeared an usurper of the most peculiar kind: his vicar and son-in-law, Ezzelino da Romano. He stands as the representative of no system of government or administration, for all his activity was wasted in struggles for supremacy in the eastern part of Upper Italy; but as a political type he was a figure of no less importance for the future than his imperial protector Frederick. The conquests and usurpations which had hitherto taken place in the Middle Ages rested on real or pretended inheritance and other such claims, or else were effected against unbelievers and excommunicated persons. Here for the first time the attempt was openly made to found a throne by wholesale murder and endless barbarities, by the adoption, in short, of any means with a view to nothing but the end pursued. None of his successors, not even Cæsar Borgia, rivalled the colossal guilt of Ezzelino; but the example once set was not forgotten, and his fall led to no return of justice among the nations, and served as no warning to future transgressors.
It was in vain at such a time that St. Thomas Aquinas, a born subject of Frederick, set up the theory of a constitutional monarchy, in which the prince was to be supported by an upper house named by himself, and a representative body elected by the people; in vain did he concede to the people the right of revolution.[5] Such theories found no echo outside the lecture-room, and Frederick and Ezzelino were and remain for Italy the great political phenomena of the thirteenth century. Their personality, already half legendary, forms the most important subject of 'The Hundred Old Tales,' whose original composition falls certainly within this century.[6] In them Frederick is already represented as possessing the right to do as he pleased with the property of his subjects, and exercises on all, even on criminals, a profound influence by the force of his personality; Ezzelino is spoken of with the awe which all mighty impressions leave behind them. His person became the centre of a whole literature from the chronicle of eyewitnesses to the half-mythical tragedy[7] of later poets.
Immediately after the fall of Frederick and Ezzelino, a crowd of tyrants appeared upon the scene. The struggle between Guelph and Ghibelline was their opportunity. They came forward in general as Ghibelline leaders, but at times and under conditions so various that it is impossible not to recognise in the fact a law of supreme and universal necessity. The means which they used were those already familiar in the party struggles of the past--the banishment or destruction of their adversaries and of their adversaries' households.
