When commenting on the issue of ecumenicity, Nicea II essentially gives the teaching that all five Patriarchs of the Pentarchy and their synods must receive the council, and that the same council must have it’s teaching go out (and be received presumably) throughout the Earth. The role of the Roman synod is said to be that of cooperation inasmuch as they ultimately receive the council, but the actual working out of doctrine belongs to the other Patriarchates.

Whatever the weaknesses of this definition, especially considering the growth in the number of Patriarchates throughout Orthodox Christian history and the collapse in numbers of the ancient Pentarchy to the point that by the 16th ceturry Jerusalem had only three bishops total at that point and Alexadria a mere two, (Panchenko, Arab Orthodox Christians Under the Ottomans, p. 68-69), this is the only definition of ecumenicity that is ever given by an Ecumenical Council. In fact, if one reviews the next Ecumenical Council’s observations on the same question, Constantinople 879-880, it merely reiterates the same. It also adds the idea a council must be Orthodox inasmuch as it is consistent with the teaching of the fathers, addresses dogmatic questions, and properly follows conciliar procedure; but this is to be expected. Surprisingly, Photius adds the cooperation of the Eastern Roman Emperors, perhaps not prescriptively, but clearly presuming upon it nevertheless.

As follows are quotations from an early translation of the council by Uncut Mountain Press. The Acts of the Eighth Ecumenical Council, translated by Gregory Heers, is currently available for preorder–but its page numbers will presumably differ from the pre-print copy. The citations here are from the Commemorative Conference Edition, March 2024.

Who could call that [Constantinople 869-870] a council, which sat the apocrisiaries of the Sacacens as judges and lawgivers? [i.e. the fake Oriental legates] With what council could it be numbered, that which dared to act contrary to all the saints and all the Council’s, which condemned the innocent without any examination soever and confused and destroyed all laws, ecclesiastical [i.e. Church canons and precedent] and legal [i.e. Byzantine/Eastern Roman]? For this reason, the holy thrones of the East denounced and rejected its acts and delivered them over to anathema. (Elias, the Legate of Jerusalem in the Third Session, p. 87)

[Concering Nicea II’s Ecumenicity:] For just as in those councils all the hierarchical thrones came together, some in person while others through representatives, and presented the faithfulness and certainty of the dogmas, so did this one also. A representative came from the most holy pope of Rome and likewise also from our own thrones of the East, and its dogmas were related and familiar and of the same faith as those of the six OEcumenical Councils. So, whoever does not accept this Council and does not call it the seventh OEcumenical is also cancelling the others also, even if he dare not say so. (Elias, the Legate of Jerusalem in the Fifth Session, p. 108)

Since everything that ought to have been done in this holy and Oecumenical Council, by the good will of God, by the cooperation of our great and high Emperors, and by the assent and agreement of the most holy pope of Rome, our spiritual brother and father, through the presence of his most holy representatives, and of the other three eastern thrones…we give thanks to the supremely good God…(Photius in response to the Council’s third Canon in the Fifth Session, p. 115)

…my master John [VIII] the thrice-blessed of the holy Catholic and apostolic church of the Romans, the highest hierarch and oecumenical pope, in this holy and [O]ecumenical Council, as following the order, command, and approval of our most holy, apostolic, and oecumenical Pope John, and with the agreement of the holy church of the Constantinopolitans, and with the consensus of the representatives of the other three patriarchal thrones, and the joint ratification of this holy and Oecumenical Council, do accept this the most reverend Photius as lawful and canonical patriarch… (Signature of Paul, a Roman Legate, in the Fifth Session, p. 117)

[The Council in describing its own work:]…the zeal and struggle of our great and high Emperor, and by the co-operation and assistance of the most holy pope, our spiritual brother and father, and of the other hierarchal thrones…a profound peace has been awarded to the churches… (Photius during the Seventh [final] Session, p. 129)

Concluding remarks. Much can be made of honorifics in this Council. Saint Photius is called “most holy master and oecumenical patriarch” (p. 22), “worker of light and chief shepherd of the Church of God” (p. 58), “holy spiritual father” (p. 67), and etcetera. Nevertheless, what is the application to today? There is neither Rome nor an Eastern Roman Emperor. As for Roman Catholics, they also lack a legitimate Pentarchy (the council inveighing against pretenders to said Patriarchates) and a Christian Emperor as well.

I personally speculate that the operating assumption in all of these definitions is the idea of consensus-based ecclesiology. When Christendom was mostly just the ecclesiastical boundaries of the Pentarchy, making up about 75 percent of all Christians, it would make sense that the definition the Church gave included this. Furthermore, when the government of more than half of this population was Orthodox Christian and Church canons had the force of civil law, the cooperation of the government reflects this consensus. And so, the Orthodox may not have a Pentarchy anymore or an Orthodox government, but they still have consensus. This is why “the protector of religion is the very body of the Church, even the people themselves, who desire their religious worship to be ever unchanged and of the same kind as that of their fathers” (Constantinople 1848, Par 17). The Church can still reach legitimate consensus on questions of the faith even today. Ultimately, it is through this mechanism the people of God recognize the work of God in a council and appropriately recognize it as binding on the conscience.