So, in a letter to Rodolph, Duke of Suabia, who at that time was known to be secretly hostile to the king, Gregory declared that he entertained no ill feeling whatever for Henry, but simply desired to do his duty.
There were two evils which Gregory was resolved to extirpate: lay investitures, and the incontinence of the clergy.

When the power of appointing to benefices was usurped by the civil power, the emperor was sure to fill the highest places in his gift with creatures of his own.
The inevitable result of this was to create two classes of prelates--one of lay, the other of ecclesial investiture.

Its ultimate effect was to render the Church completely depend upon the State, and to change and corrupt its very source with the varying vices of libertine despots.

It was found (and how could it be otherwise ?) that the proteges of the emperor studied only how to please him; and that, in serving the State and the prince, they became indifferent to the Church.

Selected to serve a particular purpose, or chosen in consideration of a valuable donation, the lay nominee had been sure to fulfil the object for which he was elevated, or to indulge the avarice or ambition which had craved the appointment.