council · 754 · Chalcedon
Constantine V staged the council of Hieria to give iconoclasm conciliar form: 338 bishops, with every patriarchal see absent or vacant, declared the icon a christological error. It called itself the seventh ecumenical council; thirty-three years later Nicaea II read its definition aloud — and refuted it clause by clause.
The Council of Hieria was a Christian council of 754 which viewed itself as ecumenical, but was later rejected by the Second Council of Nicaea (787) and by Roman Catholic and Eastern Orthodox churches, since none of the five major patriarchs participated. However, it is preferred over Second Nicaea by some Protestants. The council was significant in the controversy of Byzantine iconoclasm, condemning the veneration and production of religious icons as idolatrous and pagan, reflecting Byzantine Emperor Constantine V's iconoclasm. This council declared itself the 'Seventh Ecumenical Council', as did the Second Council of Nicaea.
Constantine V's case that icons are idolatry and christologically impossible.
338 bishops — no patriarch among them — anathematized the making and veneration of icons; Nicaea II would anathematize them back.