There seems to be a glaring red flag with the Church and the Council of 879.
The Eastern Orthodox claim the Roman Church originally annulled the Council of 869 at the Council of 879. Centuries later, when the Church needed to use a Canon from 869, they conveniently claimed it was never null to begin with and pretended the Council of 879 was never an Ecumenical council, despite all the conclusive evidence that it clearly was.
Roman Catholic canonists first referred to their Eighth Ecumenical Council (the Ignatian one) in the beginning of the twelfth century. In line with Dvornic and others, Meijer also explained that this was done deliberately because these canonists needed at that time canon 22 of that Council. In point of fact, however, they overlooked the fact that “this Council had been cancelled by another, the Photian Synod of 879-880 — the acts of which were also kept in the pontifical archives.” It is interesting to note that later on the Roman Catholics called this Photian Council “Conciliabulum Oecumenicum Pseudooctavum”, thereby acknowledging it implicitly as another Eighth Council rival to that of their own choice!
A letter by the Pope at the time, Pope John VIII clearly denounced the Coucil of 869
“We [Pope John VIII] wish that it is declared before the Synod, that the Synod which took place against the aforementioned Patriarch Photios at the time of Hadrian, the Most holy Pope in Rome, and [the Synod] in Constantinople [869/70] should be ostracized from this present moment and be regarded as annulled and groundless, and should not be co-enumerated with any other holy Synods.” The minutes at this point add: “The Holy Synod responded: We have denounced this by our actions and we eject it from the archives and anathematize the so-called [Eighth] Synod, being united to Photios our Most Holy Patriarch. We also anathematize those who fail to eject what was written or said against him by the aforementioned by yourselves, the so-called [Eighth] Synod.”
Catholics claim that this letter from Pope John VIII was a forgery by Photios. Once Pope John VIII realized this, he rejected the Council, excommunicated Photios for the 2nd time and started the 2nd schism.
Fr. Francis Dvornik, in his book The Photian Schism does his research and completely debunks this. He says the stories of the 2nd ex-communication didn’t come up until the 11th Century until Catholics “started” them in attempt to make the 879 Council that condemned the Filique look un-ecumenical
I don’t know who to believe in this, and I’d hate to think that our Catholic historians have been revising and distorting history