Henry, rebelled against by his sons, died broken-hearted like his enemy; and for half a century the strife over "lay investitures" was carried on by popes and emperors. The papacy had thus become the evil genius at once of Italy and of Germany, entering into and intensifying every Italian feud, and giving to German feudalism a fatal ground of combat for centuries. Out of all the strife the papacy made ultimate profit. When the war of the investitures was over, it built up the Decretum of the monk Gratian, a code embodying the Isidorean frauds with others, such as the gross pretence that St. Augustine had declared the Decretals to be of the same status with the canonical scriptures. The war, meantime, had ended in a compromise from which also the papacy substantially gained. The result was to turn it ere long into a vast system of financial exploitation. Every evil in the way of simony and corruption against which Hildebrand had revolted was further developed under papal auspices. The people lost all power of electing their bishops; and the rich chapters, on whom the right devolved, became the field of simony for the nobles; while the pope drew from the sale of his ratifications an immense revenue. So rapid was the effect of the new relation that by the middle of the twelfth century the bulk of the current literature of Europe, serious and satirical, was bitterly hostile to Rome, which now impressed many instructed men chiefly as a great machine for extortion. While the Church officially denounced usury, its own usurers were everywhere drawing interest from prelates who had had to borrow money to buy their investitures. The pretence of making the clergy "unworldly" by enforced celibacy was under such circumstances not edifying. Needless to say, while clerical marriage could be officially put down, clerical concubinage was not.
The strength of the papacy as against its many enemies lay (1) in the strifes of States and nations, in which the pope could always intervene; (2) in the feeling of many serious men that a central power was needed to control strife and tyranny; (3) in the compiled system of canon law, which expanded still further the code of the Decretals and of Gratian, and constantly exalted the papal power; (4) in the orders of preaching friars, who acted as papal emissaries, and kept in partial discredit the local clergy everywhere; and (5) in the power of the pope to appeal to the worst motives of ignorant believers. Thus at the beginning of the thirteenth century Innocent III, a zealous champion of the papal power, was able in the teeth of the common hostility of educated men to evoke an immense outburst of brutal fanaticism by offering indulgences, spiritual and temporal, to all who would join in a crusade of massacre against the Albigensian and other heretics of Languedoc, where the Paulician and other anti-clerical doctrines had spread widely. Twenty years of hideous bloodshed and demoralization went far to create an atmosphere in which criticism could not breathe; and the whole evocation of the eastern Crusades, both before and after this period, was carried on by the popes with a clear perception of the gain to their authority from the armed consensus of Christendom under their appeal, on the proffer of indulgences. They had hoped to extend their rule over the East, Christian and paynim; but though this dream came to nothing they were nonetheless aggrandized by the effort. The revived pretensions to dispose of all unclaimed territory on the globe, to depose heretic princes, and to confer sovereignties, were all reinforced.