The first Ecumenical Council (a council of Christian bishops convened in Nicaea by the Roman Emperor Constantine I in AD 325. This first ecumenical council was the first effort to attain consensus in the church through an assembly representing all of Christendom.)
One of the most beautiful stained glass windows in USA is found in St. Mary's Basilica, a Roman Catholic church in Covington, KY. The Cathedral's north transept window is the world's largest church stained glass window, measuring 67 feet in length by 24 feet wide. It presents the early fifth century Ecumenical Council of Ephesus that proclaimed Mary as the Mother of God.