The Council of Constantinople (879-880)

Held under St Photios the Great, with legates sent by Pope John VIII. It restored Photios to his see, annulled the council of 869-870 that had deposed him, and anathematised anyone who should add to or take from the Nicene-Constantinopolitan Creed, which is a condemnation of the Filioque before the Filioque had become a quarrel. John VIII accepted its decisions; Rome repudiated it in the eleventh century and now counts the council of 869-870 as its eighth. Many Orthodox reckon this council the Eighth Ecumenical Council, and that reckoning is not universally settled among them.