Dionysius of Rome

Origen of Alexandria (185-254 CE) was probably one of the most gifted theologians in the Greek-speaking Mediterranean world that formed the backdrop of the early Christian church. When Origen's writings on the nature of the Trinity bordered on heterodoxy, the bishop of Rome called a synod. Origin insisted that God the Father is the God, while God the Son—the "Logos"—is simply God. Dionysius of Rome relied on his privileged position as twenty-sixth bishop of Rome to challenge Origen, since if God the Son was not truly equal to God the Father, then humanity's redemption was in doubt. Dionysius wrote a letter to the bishop of Alexandria affirming three points that outlined the principles of orthodoxy: 1) There is one Lord. 2) Jesus Christ is the Lord. 3) Christ the Lord is the Son, and as such is distinct from the Father who is also the Lord.
Sources: Richard P. McBrien. Catholicism. San Francisco: HarperCollins, 1994. Pp 286-287.