The Catholic Creed: Nicene Creed at the first Nicene council - 325 A.D,
We believe in one God, the Father Almighty, Maker of all things visible and invisible. And in one Lord Jesus Christ, the Son of God, begotten of the Father, the only-begotten; that is, of the essence of the Father, God of God, Light of Light, very God of very God, begotten, not made, being of one substance with the Father; by whom all things were made both in heaven and on earth; who for us men, and for our salvation, came down and was incarnate and was made man; he suffered, and the third day he rose again, ascended into heaven; from thence he shall come to judge the quick and the dead. And in the Holy Spirit. But those who say: 'There was a time when he was not;' and 'He was not before he was made;' and 'He was made out of nothing,' or 'He is of another substance' or 'essence,' or 'The Son of God is created,' or 'changeable,' or 'alterable'—they are condemned by the holy catholic and apostolic Church.
Note this, it was the Bishops that decided the Nicene Council, not Patriarchs, much less anything called a "Pope," in the modern sense. See: The Best and Most Important Online Catholic Books: The Catholic Creed: Early Church governance and then the Canons of Nicaea and Chalcedon