Statement of belief adopted at the First Ecumenical Council in 325
Icon depicting Constantine the Great, accompanied by the bishops of the First Council of Nicaea (325), holding the Niceno-Constantinopolitan Creed of 381. First line of main text in Greek: Πιστεύω εἰς ἕνα Θ[εό]ν, πατέρα παντοκράτορα, ποιητὴν οὐρανοῦ κ[αὶ] γῆς,. Translation: "I believe in one God, the Father the Almighty, Maker of heaven and earth."
The Nicene Creed is part of the profession of faith required of those undertaking important functions within the Orthodox and Catholic[4][5] Churches. Nicene Christianity regards Jesus as divine and "begotten of the Father".[6] Various conflicting theological views existed before the fourth century and these spurred the ecumenical councils which eventually developed the Nicene Creed, and various non-Nicene beliefs have emerged and re-emerged since the fourth century, all of which are considered heresies[7] by adherents of Nicene Christianity.
^Cone, Steven D.; Rea, Robert F. (2019). A Global Church History: The Great Tradition through Cultures, Continents and Centuries. Bloomsbury Publishing. pp. lxxx. ISBN978-0-567-67305-3.
^World Encyclopaedia of Interfaith Studies: World religions. Jnanada Prakashan. 2009. ISBN978-81-7139-280-3. In the most common sense, "mainstream" refers to Nicene Christianity, or rather the traditions which continue to claim adherence to the Nicene Creed.