It feigned that the Emperor Constantine, in gratitude for his cure from leprosy, and baptism by Pope Sylvester, had bestowed Italy and the Western provinces on the pope, and that, in token of his subordination, he had served the pope as his groom, and led his horse some distance.

This forgery was intended to work on the Frankish kings, to impress them with a correct idea of their inferiority, and to show that, in the territorial concessions they made to the Church, they were not giving but only restoring what rightfully belonged to it.
The most potent instrument of the new papal system was Gratian's Decretum, which was issued about the middle of the twelfth century.

It was a mass of fabrications.

It made the whole Christian world, through the papacy, the domain of the Italian clergy.

It inculcated that it is lawful to constrain men to goodness, to torture and execute heretics, and to confiscate their property; that to kill an excommunicated person is not murder; that the pope, in his unlimited superiority to all law, stands on an equality with the Son of God! As the new system of centralization developed, maxims, that in the olden times would have been held to be shocking, were boldly avowed--the whole Church is the property of the pope to do with as he will; what is simony in others is not simony in him; he is above all law, and can be called to account by none; whoever disobeys him must be put to death; every baptized man is his subject, and must for life remain so, whether he will or not.