Commemoration

During most of the history of the Church, important bishops in communion with each other would pray for one another during their liturgies. In the Greek-speaking Eastern Roman Empire, this was done via a list engraved on folded bronze plates, known therefore as diptychs. 

For many hundreds of years, likely from the fourth century to the eleventh, the Pope was commemorated on the diptychs of the Church of Constantinople. Every Pope upon election would duly write a letter to the bishop of Constantinople, and vice versa, and each would duly inscribe the name of the new holder of the see on their respective lists. While the Pope's inscribing on the diptychs did not in itself constitute the bond of communion--demonstrated via Eucharistic participation--and was not strictly necessary to it, it nonetheless was one of the most immediate signs of unity between the bishop of New Rome and the acknowledged First See of Christendom that the Pope was regularly commemorated at the altars of Constantinople.

Then he stopped being commemorated. And the truth is, no one really knows why or how it happened.

In 1054, the Patriarch of Constantinople Michael Cerularius wrote to the Patriarch of Antioch Peter and informed him that Constantinople no longer commemorated the Pope on its diptychs, and that he should do likewise. According to Cerularius, though, he himself was in no way responsible for this state of affairs: rather, the Church of Constantinople had simply not commemorated the Pope since the Fourth Ecumenical Council hundreds of years before.

Peter of Antioch wrote back in open bafflement. From Cerularius' description, it was clear that he had meant the Fifth Ecumenical Council, not the Fourth--and he also seemed to be unaware that though there had been a brief breaking of communion between Rome and Constantinople at that time, communion and commemoration had been quickly restored. And Peter could swear to eyewitness testimony that, at least as late as a few decades before, Rome had still been commemorated in Constantinople. 

A few decades later, in 1089, the Byzantine Emperor Alexios I Komnenos the Byzantine Emperor, in an attempt to improve relations with Rome, summoned the Holy Synod of Constantinople and asked the assembled bishops why the Pope was no longer commemorated in the diptychs of Constantinople, when this act had taken place, and if there was any reason why they should not add the Pope back again. In reply, the assembled bishops claimed to have been able to find no records at all of any ecclesiastical act carrying this out, and indeed no evidence whatsoever of when or how or why such an event had taken place. They asked, nonetheless, that the status quo be allowed to stand--and though the Emperor refused and ordered them to commemorate the Pope again, the matter was put off for a time.

Some scholars have argued, plausibly enough, that it was in fact Cerularius who took the name out, and that he then simply lied about having done so--though how he was able to do so while leaving no ecclesiastical record must remain a mystery. Others propose that the name was merely left off by mistake at some point in the decades prior to Cerularius' reign--in my judgment an utter absurdity given the nature of ecclesiastical life and the relations between Rome and Constantinople during the period.

During the ensuing centuries, though, the Pope's name was added back at times, and taken out again: but the norm came to be a lack of commemoration, not the opposite. Contrary to popular belief, though, at no point was any formal excommunication of the Pope ever carried out by anyone. Following the Council of Florence and the official Union in the 15th century, however, the Pope's name was once again added--then taken out again during the reaction against that Council in Constantinople, then added and removed repeatedly over the ensuing decades according to the dictates of policy. Not long before the Fall of Constantinople, the Union was once again proclaimed: and there can be little doubt that at the final Divine Liturgy celebrated in the Hagia Sophia, for the Emperor and both Greek and Latin defenders, included the commemoration of the Pope. 

Then the City fell, and the conquering Turks appointed the most anti-Roman ecclesiastic they could find to the office of Patriarch, and absolutely forbade any contacts with Rome: and they saw to it that the Church of Constantinople never again prayed for the Pope by name over all the ensuing more than five centuries: until last week.

On November 29, 2025, Pope Leo XIV participated in a public prayer service and Doxology at the headquarters of what remains of the Church of the Constantinople: which today, in the City itself, amounting to a tiny body of only a few thousand, dwarfed many times over by the (mostly migrant) Latin and Armenian and Chaldean Catholics present in the metropolitan area. At this Doxology, during the litany of hierarchs, the Pope was once again commemorated and prayed for by name as the "holy bishop and Pope of Rome Leo," in the litany's first position, just ahead of the Patriarch of Constantinople. And, at least for a moment, things were once again as they had been in 1453 and 1000 and 500 AD.

Of course, this is not (yet) full communion: but it is still a remarkable event, worthy of notice.