Emperor Justinian
Papal Supremacy, Apostolic See, St. Peter
“Yielding honor to the Apostolic See and to Your Holiness, and honoring your Holiness, as one ought to honor a father, we have hastened to subject all the priests of the whole Eastern district, and to unite them to the See of your Holiness, for we do not allow of any point, however manifest and indisputable it be, which relates to the state of the Churches, not being brought to the cognizance of your Holiness, since you are the Head of all the holy Churches.” (Written to Pope Hormisdas, Justinian Epist. ad. Pap. Joan. ii. Cod. Justin. lib. I. tit. 1 [c. A.D. 520–533]).
A different translation of the above quote with expanded context:
“With honor to the Apostolic See, and to your Holiness, which is, and always has been remembered in Our prayers, both now and formerly, and honoring your happiness, as is proper in the case of one who is considered as a father, We hasten to bring to the knowledge of Your Holiness everything relating to the condition of the Church, as We have always had the greatest desire to preserve the unity of your Apostolic See, and the condition of the Holy Churches of God, as they exist at the present time, that they may remain without disturbance or opposition. Therefore, We have exerted Ourselves to unite all the priests of the East and subject them to the See of Your Holiness, and hence the questions which have at present arisen, although they are manifest and free from doubt, and according to the doctrines of your Apostolic See, are constantly firmly observed and preached by all priests, We have still considered it necessary that they should be brought to the attention of Your Holiness. For we do not suffer anything which has reference to the state of the Church, even though what causes difficulty may be clear and free from doubt, to be discussed without being brought to the notice of Your Holiness, because you are the head of all the Holy Churches, for We shall exert Ourselves in every way (as has already been stated), to increase the honor and authority of your See.” (Written to Pope Hormisdas, Justinian Epist. ad. Pap. Joan. ii. Cod. Justin. lib. I. tit. 1 [c. A.D. 520–533])
“Let your Apostleship show that you have worthily succeeded to the Apostle Peter, since the Lord will work through you, as Surpreme Pastor, the salvation of all.” (Coll. Avell. Ep. 196, July 9th, 520, Justinian to Pope Hormisdas).
“Now do we allow that any of these things, concerning ecclesiastical institution, should fail to be brought before his Holiness, as being the head of all the holy Priests of God, and because as often as heretics have arisen in these parts, Justinian have been repressed by the sentence and judgment of that holy See.” ( Justinian, Epistles, Ad Epiphan. Cod. Justinian, lin. I. ton. I. n. 7).
“[Rome is] the source of the priesthood…the venerable See of the most high Apostolic Peter.” (Epistle to Pope Agapetus).
“The ancient city of Rome has the honor of being the mother of our laws, and no one can doubt that in it the summit of the supreme pontificate lies. This is why we have also found it necessary to honor this cradle of the law, this source of the priesthood, by a special decree of our sacred will.” (Justinian Code, Novel 9 [c. A.D. 535]).