Ireneaus of Lyons was one of the great Fathers of the Church in the second century. He was a bishop and greatly influenced the development of Christian theology.


Ireneaus was born in Asia Minor and was a disciple of Policarp, one of the renowned Christian teachers, who died a martyr's death. He wrote in Greek and among his important writings are those that defend the Christian faith. Ireneaus was greatly aware of the importance of the writings of Israel and he formulated a theology that united the New Testament with the Old Testament – a unity that is indissoluble. From his perspective, the Old Testament constitutes an immense prophecy pointing to Jesus as the Messiah of Israel and the Son of God.

Saint Irenaeus wrote: "God's glory is in living men and full life for men is in the vision of God" (from Book 4, Against Heresies).