The Second Ecumenical Council: [[Constantinople I|First Council of Constantinople]] 381 convened by the Roman Emperor of the East [[Theodosius I]]. Neither the Holy Father Pope Saint [[Damasus I]] or his papal legates attended. Already the split between East and West was manifesting itself. 186 bishops did attend, including [[Saint Gregory Nazianzen]] and Saint [[Cyril of Jerusalem]].
The Third Ecumenical Council: [[Council of Ephesus]] 431 called by the Roman Emperor of the East Theodosius II, influenced by his saintly sister [[Saint Pulcheria]], in harmony with Pope [[Saint Celestine I]].
The Fourth Ecumenical Council: [[Council of Chalcedon]] 451called by the Roman Emperor of the East [[Marcian]], influenced by his wife Saint Pulcheria, in coordination with Pope [[Saint Leo the Great]].
The Fifth Ecumenical Council: [[Constantinople II|Second Council of Constantinople]] 553