In these two principles, the reformers sought to purify the church from worldly influence: influence from secular authorities in the first place (hence the doctrine that the Pope of Rome, himself at the head of all other bishops due to Peter’s confession of faith to Christ, was also above secular governments, and had the right and duty to depose them if they failed in their function), but also simony and the investiture of the clergy by laymen.

The starting-point of all the programs of reform started with the doctrine that the Church is the Body of Christ. The issue at stake is participation in that Body. Thus we can distinguish three areas in which the Gregorian reformers acted out this participation.