The First Council of Nicaea (/naɪˈsiːə/ ny-SEE-ə; Ancient Greek: Σύνοδος τῆς Νικαίας, romanized: Sýnodos tês Nikaías) was a council of Christian bishops convened in the Bithynian city of Nicaea (now İznik, Turkey) by the Roman Emperor Constantine I. The Council of Nicaea met from May until the end of July 325.
This ecumenical council was the first of many efforts to attain consensus in the church through an assembly representing all Christendom. Hosius of Corduba may have presided over its deliberations. Attended by at least 200 bishops, its main accomplishments were the settlement of the Christological issue of the divine nature of God the Son and his relationship to God the Father, the construction of the first part of the Nicene Creed, the mandating of uniform observance of the date of Easter, and the promulgation of early canon law.