IV. They announce their decision that Constantinople should take precedence next to Rome, and ask Leo's consent to it.
And we further inform you that we have decided on other things also for the good management and stability of church matters, being persuaded that your holiness will accept and ratify them, when you are told. The long prevailing custom, which the holy Church of God at Constantinople had of ordaining metropolitans for the provinces of Asia, Pontus and Thrace, we have now ratified by the votes of the Synod, not so much by way of conferring a privilege on the See of Constantinople as to provide for the good government of those cities, because of the frequent disorders that arise on the death of their bishops, both clergy and laity being then without a leader and disturbing church order.
And this has not escaped your holiness, particularly in the case of Ephesus, which has often caused you annoyance. We have ratified also the canon of the 150 holy Fathers who met at Constantinople in the time of the great Theodosius of holy memory, which ordains that after your most holy and Apostolic See, the See of Constantinople shall take precedence, being placed second: for we are persuaded that with your usual care for others you have often extended that Apostolic prestige which belongs to you, to the church in Constantinople also, by virtue of your great disinterestedness in sharing all your own good things with your spiritual kinsfolk.
Accordingly vouchsafe most holy and blessed father to accept as your own wish, and as conducing to good government the things which we have resolved on for the removal of all confusion and the confirmation of church order. For your holiness' delegates, the most pious bishops Paschasinus and Lucentius, and with them the right Godly presbyter Boniface, attempted vehemently to resist these decisions, from a strong desire that this good work also should start from your foresight, in order that the establishment of good order as well as of the Faith should be put to your account.
For we duly regarding our most devout and Christ loving Emperors, who delight therein, and the illustrious senate and, so to say, the whole imperial city, considered it opportune to use the meeting of this ecumenical Synod for the ratification of your honour, and confidently corroborated this decision as if it were initiated by you with your customary fostering zeal, knowing that every success of the children rebounds to the parent's glory. Accordingly, we entreat you, honour our decision by your assent, and as we have yielded to the head our agreement on things honourable, so may the head also fulfil for the children what is fitting.
For thus will our pious Emperors be treated with due regard, who have ratified your holiness' judgment as law, and the See of Constantinople will receive its recompense for having always displayed such loyalty on matters of religion towards you, and for having so zealously linked itself to you in full agreement. But that you may know that we have done nothing for favour or in hatred, but as being guided by the Divine Will, we have made known to you the whole scope of our proceedings to strengthen our position and to ratify and establish what we have done.
Source: Letters (New Advent)