The First Council of Nicaea was held in Nicaea , in Bithynia in 325 . Nicea is the city of Iznik in Turkey . The Roman Emperor Constantine I called the bishops of the Roman Empire to the first ecumenical [ 1] conference of the early Christian Church . It had as most important result the first uniform Christian doctrine , called the Nicene Creed .
With the creation of the creed, a precedent was established for subsequent 'general (ecumenical) councils of Bishops' (Synods ) to create statements of belief and church law. The purpose was to define unity of beliefs for the whole of Christendom .
Constantine I called the bishops of the Christian Church to Nicaea to deal with divisions in the Church. (mosaic in Hagia Sophia , Constantinople, c. 1000)
↑ Ecumenical , from Koine Greek oikoumenikos , literally meaning worldwide but generally assumed to be limited to the Roman Empire as in Augustus' claim to be ruler of the oikoumene/world; the earliest extant uses of the term for a council are Eusebius' Life of Constantine 3.6 Eusebius. Vita Constantini - Greek around 338 "σύνοδον οἰκουμενικὴν συνεκρότει " (he called for an Ecumenical council), Athanasius' Ad Afros Epistola Synodica in 369 CHURCH FATHERS: Ad Afros Epistola Synodica (Athanasius) , and the Letter in 382 to Pope Damasus I and the Latin bishops from the First Council of Constantinople NPNF2-14. The Seven Ecumenical Councils - Christian Classics Ethereal Library Archived 2009-10-29 at the Wayback Machine