Irenaeus (ca. 125-202) was bishop of Lugdunum in Gaul, which is now Lyons, France. Irenaeus was born in Smyrna in Asia Minor, where he studied under bishop Polycarp, who in turn had been a disciple of the Apostle John. Leaving Asia Minor for Rome he joined the school of Justin Martyr before being made bishop of Lyons in Southern Gaul in about ...
Irenaeus' primary goal in writing Against Heresies was to attack cults that fell away from orthodox Christianity, mainly the Gnostics and Marcionites.    In particular, he sought to disprove what he saw as incorrect interpretations of scripture on the part of Gnostics such as Valentinus. 
Saint Irenaeus, (born c. 120/140, Asia Minor—died c. 200/203, probably Lyon; Western feast day June 28; Eastern feast day August 23), Bishop and theologian. Born of Greek parents, he was a missionary to Gaul before being named bishop of Lugdunum (modern Lyon, France).
Information on Irenaeus of Lyons. Irenaeus of Lyons wrote his Against Heresies c. 175-185 CE. His work is invaluable to modern scholarship in the attempt to recover the content of Gnostic teachings in the second century. Irenaeus also provides the first explicit witness to a four-fold gospel canon.
Irenaeus (Greek: Εἰρηναῖος), (c. 120- c. 200) was a notable early Christian apologist and bishop of Lugdunum in Gaul, which is now Lyon, France. His writings were formative in the development of early Christian theology , and he is recognized as a saint by both the Eastern Orthodox Church and the Roman Catholic Church .
Summary. Irenaeus (b. c. 135) was installed as bishop of Lyons after a severe persecution of the churches of Lyons and Vienne took the life of his episcopal predecessor, Pothinus. He was not a native of Roman Gaul, but rather migrated from Asia Minor, where in his younger days he heard the Apostle John teach.
Sep 11, 2023 · Irenaeus's Demonstration of the Apostolic Preaching by Iain M. MacKenzie The theology of Irenaeus, and the Demonstration of the Apostolic Preaching in particular, is pivotal in showing the way in which the fathers of the church interpreted scripture and distilled doctrine. The Demonstration is an important hinge showing how the doctrine of the fourth century with its definitive councils and ...