The Council of Hieria of 754, held at the imperial palace of that name close to Chalcedon in Anatolia, was summoned by Byzantine Emperor Constantine V and was attended by 338 bishops, who regarded it as the seventh ecumenical council The Second Council of Nicaea, which annulled that of Hieria, was itself annulled at a synod held in 815 in Constantinople under Emperor Leo V. This synod, presided over by Patriarch Theodotus I of Constantinople, declared the Council of Hieria to be the seventh ecumenical council, but, although the Council of Hieria was called by an emperor and confirmed by another, and although it was held in the East, it later ceased to be considered ecumenical.