The Anti-Icon Church Council of Chalcedon (Kadıköy, Istanbul) (AD 754)
In 754, emperor Constantine V convened an anti-icon church council in the imperial palace built by emperor Justinian at Hieria (modern Kadıköy, Istanbul). There are only a few remains of the palace complex today. The council was attended by around three hundred and thirty bishops and endorsed Constantine V’s anti-icon position. However, it was not accepted as an official Ecumenical Church Council because no patriarchs were present from any of the five key church centers of the Roman Empire: Rome, Constantinople, Antioch, Alexandria, or Jerusalem.