=17.= That no action of a synod, and no book, may be considered canonical without his authority.[380] =18.= That his decree can be annulled by no one, and that he alone may annul the decrees of any one. =19.= That he can be judged by no man. =20.= That no one shall dare to condemn a person who appeals to the apostolic see. =22.= That the Roman Church has never erred, nor ever, by the testimony of Scripture, shall err, to all eternity.[381] =26.= That no one can be considered Catholic who does not agree with the Roman Church. =27.= That he [the Pope] has the power to absolve the subjects of unjust rulers from their oath of fidelity. 46. Letter of Gregory VII. to Henry IV. (December, 1075) The high ideal of papal supremacy over temporal sovereigns which Gregory cherished when he became pope in 1073, and which is set forth so forcibly in the _Dictatus_, was one whose validity no king or emperor could be brought to recognize. It involved an attitude of inferiority and submissiveness which monarchs felt to be quite inconsistent with the complete independence which they claimed in the management of the affairs of their respective states. Perhaps one may say that the theory in itself, as a mere expression of religious sentiment, was not especially obnoxious; many an earlier pope had proclaimed it in substance without doing the kings and emperors of Europe material injury. It was the firm determination and the aggressive effort of Gregory to reduce the theory to an actual working system that precipitated a conflict.