Up to the end of the twelfth century, the popes were the vicars of Peter; after Innocent III.

they were the vicars of Christ.
But an absolute sovereign has need of revenues, and to this the popes were no exception.

The institution of legates was brought in from Hildebrand's time.

Sometimes their duty was to visit churches, sometimes they were sent on special business, but always invested with unlimited powers to bring back money over the Alps.

And since the pope could not only make laws, but could suspend their operation, a legislation was introduced in view to the purchase of dispensations.