Even before Gregory VII's time it might have been predicted that two such potentates as the Emperor and the Pope, closely bound together, yet each with pretensions wide and undefined, must ere long come into collision. The boldness of that great pontiff in enforcing, the unflinching firmness of his successors in maintaining, the supremacy of clerical authority, inspired their supporters with a zeal and courage which more than compensated the advantages of the Emperor in defending rights he had long enjoyed. On both sides the hatred was soon very bitter. But even had men's passions permitted a reconciliation, it would have been found difficult to bring into harmony adverse principles, each irresistible, mutually destructive. As the spiritual power, in itself purer, since exercised over the soul and directed to the highest of all ends, eternal felicity, was entitled to the obedience of all, laymen as well as clergy; so the spiritual person, to whom, according to the view then universally accepted, there had been imparted by ordination a mysterious sanctity, could not without sin be subject to the lay magistrate, be installed by him in office, be judged in his court, and render to him any compulsory service. Yet it was no less true that civil government was indispensable to the peace and advancement of society; and while it continued to subsist, another jurisdiction could not be suffered to interfere with its workings, nor one-half of the people be altogether removed from its control. Thus the Emperor and the Pope were forced into hostility as champions of opposite systems, however fully each might admit the strength of his adversary's position, however bitterly he might bewail the violence of his own partisans. There had also arisen other causes of quarrel, less respectable but not less dangerous. The pontiff demanded and the monarch refused the lands which the Countess Matilda of Tuscany had bequeathed to the Holy See; Frederick claiming them as feudal suzerain, the Pope eager by their means to carry out those schemes of temporal dominion which Constantine's donation sanctioned, and Lothar's seeming renunciation of the sovereignty of Rome had done much to encourage. As feudal superior of the Norman kings of Naples and Sicily, as protector of the towns and barons of North Italy who feared the German yoke, the successor of Peter wore already the air of an independent potentate. [Sidenote: Contest with Hadrian IV.]