You say that Trullo - a council which never received acceptance in the universal Church, nor was confirmed by the Apostolic See, and so fails the tests of St. Irenaeus and St. Vincent of Lerins - is God-inspired, but you refuse to treat Constantinople III as God-inspired when it declared Pope St. Agatho's letter teaching the infallibility of the Apostolic Roman See "divinely written as by the Chief of the Apostles" and announced to the Emperor: "But the highest prince of the Apostles fought with us: for we had on our side his imitator and the successor in his see, who also had set forth in his letter the mystery of the divine word. For the ancient city of Rome handed thee a confession of divine character, and a chart from the sunsetting raised up the day of dogmas, and made the darkness manifest, and Peter spoke through Agatho". Why is that?
And therefore I beseech you with a contrite heart and rivers of tears, with prostrated mind, deign to stretch forth your most clement right hand to the Apostolic doctrine which the co-worker of your pious labours, the blessed apostle Peter, has delivered, that it be not hidden under a bushel, but that it be preached in the whole earth more shrilly than a bugle: because the true confession thereof for which Peter was pronounced blessed by the Lord of all things, was revealed by the Father of heaven, for he received from the Redeemer of all himself, by three commendations, the duty of feeding the spiritual sheep of the Church; under whose protecting shield, this Apostolic Church of his has never turned away from the path of truth in any direction of error, whose authority, as that of the Prince of all the Apostles, the whole Catholic Church, and the Ecumenical Synods have faithfully embraced, and followed in all things; and all the venerable Fathers have embraced its Apostolic doctrine, through which they as the most approved luminaries of the Church of Christ have shone; and the holy orthodox doctors have venerated and followed it, while the heretics have pursued it with false criminations and with derogatory hatred. This is the living tradition of the Apostles of Christ, which his Church holds everywhere, which is chiefly to be loved and fostered, and is to be preached with confidence, which conciliates with God through its truthful confession, which also renders one commendable to Christ the Lord, which keeps the Christian empire of your Clemency, which gives far-reaching victories to your most pious Fortitude from the Lord of heaven, which accompanies you in battle, and defeats your foes; which protects on every side as an impregnable wall your God-sprung empire, which throws terror into opposing nations, and smites them with the divine wrath, which also in wars celestially gives triumphal palms over the downfall and subjection of the enemy, and ever guards your most faithful sovereignty secure and joyful in peace. For this is the rule of the true faith, which this spiritual mother of your most tranquil empire, the Apostolic Church of Christ, has both in prosperity and in adversity always held and defended with energy; which, it will be proved, by the grace of Almighty God, has never erred from the path of the apostolic tradition, nor has she been depraved by yielding to heretical innovations, but from the beginning she has received the Christian faith from her founders, the princes of the Apostles of Christ, and remains undefiled unto the end, according to the divine promise of the Lord and Saviour himself, which he uttered in the holy Gospels to the prince of his disciples: saying, “Peter, Peter, behold, Satan hath desired to have you, that he might sift you as wheat; but I have prayed for thee, that (thy) faith fail not. And when thou art converted, strengthen thy brethren.” Let your tranquil Clemency therefore consider, since it is the Lord and Saviour of all, whose faith it is, that promised that Peter’s faith should not fail and exhorted him to strengthen his brethren, how it is known to all that the Apostolic pontiffs, the predecessors of my littleness, have always confidently done this very thing: of whom also our littleness, since I have received this ministry by divine designation, wishes to be the follower, although unequal to them and the least of all. ...Who does not hate, and rage against, and avoid such blind errors, if he have any desire to be saved and seek to offer to the Lord at his coming a right faith? Therefore the Holy Church of God, the mother of your most Christian power, should be delivered and liberated with all your might (through the help of God) from the errors of such teachers, and the evangelical and apostolic uprightness of the orthodox faith, which has been established upon the firm rock of this Church of blessed Peter, the Prince of the Apostles, which by his grace and guardianship remains free from all error, [that faith I say] the whole number of rulers and priests, of the clergy and of the people, unanimously should confess and preach with us as the true declaration of the Apostolic tradition, in order to please God and to save their own souls.
Where are the Orthodox who accept all of St. Agatho's letter today? They are in the Catholic Church, because only there is the true apostolic teaching found. "O Timothy, keep that which is committed to thy trust, avoiding the profane novelties of words and oppositions of knowledge falsely so called. Which some promising, have erred concerning the faith" (1 Tim. 6:20-1).
If Trullo - a doubtful synod - is to be treated as such an authority on every matter of history, etc., why does not the III Synod of Constantinople, certainly received by all the Church catholic and the Apostolic See of Rome, not receive the same treatment? The Holy Roman Church "has never erred from the path of the apostolic tradition, nor has she been depraved by yielding to heretical innovations, but from the beginning she has received the Christian faith from her founders, the princes of the Apostles of Christ, and remains undefiled unto the end, according to the divine promise of the Lord and Saviour himself". Amen.
"You say that Trullo - a council which never received acceptance in the universal Church, nor was confirmed by the Apostolic See, and so fails the tests of St. Irenaeus and St. Vincent of Lerins...blah blah blah"
Above assumes facts not in evidence.
1) Trullo received acceptance of all of the patriarchates except the West.
2) The Patriarchate of the West subsequently left the Church and re-established itself as "The [Roman] Catholic Church".
3) I'm not sure about this test of St. Irenaeus you speak of (please quote it or link me to it), but the Council in Trullo does meet the test of St. Vincent of Lerins as to universality and consent. And as it conflicts with no earlier council, it also meets the test of St. Vincent as to antiquity.
4) Nothing in the Tradition requires confirmation by any particular see. Such a requirement would be an absurdity because if this or that see should fall into heresy, such a requirement would mean everyone would have to follow along, "Willy Nilly". If that were so, there would be no need for the Vincentian Canon.
Now you speak of some council or other that you think the Orthodox do not accept but should accept. I think you said the III Council of Constantinople. According to my information III Constantinople was received by the Church as Ecumenical. There is nothing, however, in the acts of this council that requires anyone to believe that the Pope of Rome is infallible or that the Pope of Rome and his entire jurisdiction (the Patriarchate of the West), cannot fall into heresy. Just ask any member of the Old Catholic Church of Utrecht and that Old Catholic will tell you exactly the same thing.