Can you provide proof that this Council was approved by the Pope? Even in the Orthodox model the Council has to be approved by all five patriarchs before it becomes ecumenical.
The Catholic disctionary: Eighth Ecumenical Council: Constantinople IV (869)
The Fourth General Council of Constantinople, under Pope Adrian II and Emperor Basil numbering 102 bishops, 3 papal legates, and 4 patriarchs, consigned to the flames the Acts of an irregular council (conciliabulum) brought together by Photius against Pope Nicholas and Ignatius the legitimate Patriarch of Constantinople; it condemned Photius who had unlawfully seized the patriarchal dignity. The Photian Schism, however, triumphed in the Greek Church (whatever that means - Catholic spin I guess), and no other general council took place in the East.
The last part means that according to the Catholics their councils were THEE ecumenical councils after that. The Catholics recognize 21 Ecumenical councils!!! - 13 more "ecumenical" councils after the 8th and true last one!
Again from the Catholic dictionary online:
It appears that what the Catholic spin means by "The Photian Schism, however, triumphed in the Greek Church" is that the Orthodox called the Latins heretics as Photius once did.
"We see, too, how well Photius's idea of calling Latins heretics had been learned. Caerularius had a list, a longer and even more futile one, of such accusations. His points were different from those of Photius; (So how can that be the same schisim!! Shame on the Catholic encyclopedia compilers) he had forgotten the Filioque - (At this point I have to laugh. The Patriarch could not forget what never existed in the Creed!)".
"Can you provide proof that this Council was approved by the Pope? Even in the Orthodox model the Council has to be approved by all five patriarchs before it becomes ecumenical."
This is also a question in the Orthodox Churches. For this reason we speak of the One Church, with us as its continuation, as "The Church of the 7 Councils". An argument can be made, and indeed has been made, that the 8th Council was a very large and important Local Council. Personally, I don't know that I buy that, but it is an open question.