The system was a long time dying. It was helped to die by the quarrel between the Pope and the Emperor, and by the Crusades. It may be said roughly that the feudal system in its full theoretic form never existed anywhere. That it did not, that it was so constantly modified and changed, was due to the fact that feudalism, excellent as a theory, in practice needed universal authority. When the land tenure system of the Germanic tribes was evolving into the feudal system, the endeavour was made to obtain a double overlordship by the strait alliance and interdependence of the Church and the Holy Roman Empire. The Holy Roman Emperor was in theory the elect of God. In practice he was the head of a German feudal system which evolved into a confederation of German states, instead of being the universal emperor who was the overlord of kings. The claim was indeed made by more than one emperor, but it was not recognised, because the quarrel with the Church made any recognition impossible, even if the conception of a transcendent secular unity of Christendom had been granted. The Empire could have become a reality only if there had been a succession of great emperors and great popes fully conscious of the mutual advantage of the dual arrangement, and capable of evolving a practice to unit it. The tenth century saw a weak papacy and strong emperors. The scandal of evil-living popes and the struggles of Italian noble houses for the chair of St. Peter provoked the intervention of the Empire under the Ottos, who had to intervene forcibly to prevent the Papal government falling into a sheer chaos that might have ruined much more than Rome. By the fault of the Popes themselves the emperor acquired a superior dominium which increased, till, in effect, as far as Rome was concerned, the emperor regulated the domestic affairs of the universal Church, and over the Church in his own domain acquired an authority which no Pope worthy of being at the head of a universal Church could brook. Nor could other nations brook the existence of a Papal religious power which was in fact a mere tool of the Empire. Things went so far that the Emperor Henry III. had to depose summarily three ecclesiastics, each of whom claimed to be Pope, and instal his own nominee. That roused the Papacy. It reformed itself by giving the duty of election to the College of Cardinals (1059), and by producing a great Pope in Hildebrand, enthroned as Gregory VII. in 1073.