Pope Hadrian II

“Although we have read of the Roman pontiff having passed judgement on the bishops of all the churches, we have not read of anyone having passed judgement on him. For even though Honorius was anathematized after this death by the easterners, it should be known that he had been accused of heresy, which is the only offence where inferiors have the right to resist the initiatives of their superiors or are free to reject their false opinions, although even in this case no patriarch or other bishop has the right of passing any judgement on him unless the consent of the pontiff of the same first see has authorized it.” (Pope Adrian II speaking at the Roman Synod of A.D. 869-70, from the Acts of Constantinople IV, ed. Leonardi, 238).