‘We have been placed in such a position’, wrote Pope Gregory VII at the beginning of his pontificate, ‘that we are compelled willy-nilly to announce truth and justice to all peoples, especially Christians, according to the Word of the Lord, “Cry aloud and do not cease; lift up your voice like a trumpet and announce to my people their sins” (Isaiah lviii. I), and elsewhere, “If you do not announce to the evildoer his iniquity, I shall seek his soul at your hand” (Ezekiel iii. 18). Again the prophet says, “Cursed be the man who holds back his sword from blood” (Jeremiah xlviii. 10); that is, the word of preaching from the rebuke of carnal men.’ These prophetic texts recur throughout the Register of Gregory VII, defining that obligation of rebuking evil-doers which the pope considered to be a primary duty of his office. Gregory VII was the most energetic propagandist of his reforming programme for the extirpation of simony and clerical marriage. His letters were intended to provide their recipients with anctoritates demonstrating the righteousness of the Gregorian cause.