Everything combined to encourage Innocent's interference, and it may be pointed out at once that his success was largely due to the selfish ambitions and desires of the lay princes, which enabled him to pose as the undoubted representative of moral force organised in the Church. In all his most important acts he was the mouthpiece of popular opinion. Thus his contest with Philip of France in favour of the repudiated Ingebiorg commanded the sympathy of every right-thinking person in Europe; his desire for the separation of Italy and Germany under different rulers was popular in Italy; while to attempt an union of the Churches of East and West, to crush out heresy in the south of France and elsewhere, to promote a new crusade in the East, were all regarded as duties falling strictly within the papal sphere. [His claim for the Papacy.] The importance of this great activity lies in the fact that it was based upon the most advanced theories of papal power. It was the controversy over lay investiture which first caused the defenders of the Church to formulate their views of the sphere of ecclesiastical influence as against the influence of the secular authority. But the extreme claims put forward for the Papacy as the head of the Church, by Gregory VII and his followers, had provoked the counter definitions of the jurists of Bologna on behalf of the imperial power. But the claim of universal dominion by the Emperor was contradicted by facts, and never rose above the dignity of an academic thesis; whereas in the century which elapsed from the days of Gregory VII to those of Innocent III the papal power was becoming an increasing reality in the Church. It is indeed a little difficult to see wherein it was possible for any successor of Gregory VII to make an advance upon the claims put forward by that Pope. Gregory in fond of pointing out that the power of binding and loosing given to St. Peter was absolutely comprehensive, including all persons and secular as well as spiritual matters. Innocent tells the Patriarch of Constantinople that the Lord left to Peter not only the whole Church, but the whole world to govern. To the Karolingian age it was the Emperor who was the Vicar of God. The Church reformers, while attacking this title, do not seem to have claimed in words for the Pope a higher title than Vicar of St. Peter. Innocent, however, more than once asserts that he is the representative "not of mere man, but of very God." In fact, such development as is to be found in the papal office during the twelfth century consists merely in making rather more explicit positions which have already been asserted. Gregory, in writing to William the Conqueror, had used the figures of the sun and moon to illustrate the relations of Church and State. Innocent draws out the analogy in much detail: "As God, the builder of the universe, has set up two lights in the firmament of heaven, the greater light to rule the day and the