Irenaeus (Greek: Εἰρηναῖος) was a 2nd century Christian Theologian from Smyrna in Asia Minor, now İzmir, Turkey, he was raised in a Christian family. The exact dates of his birth and death are not certain but he probably was born between 125 and 133 AD and died at around 202 AD.

Irenaeus was the second bishop of Lugdunum in Gaul modern day Lyon(France).Irenaeus is most famously known for his book written at about 180 called Adversus Haereses (Against Heresies) he wrote this book against the Gnostic heresy that seemed to be a threat to church in the early development of Christian Theology. In this Book Irenaeus mentions Valentinus who was a leader of the valentinian Gnostics. The book is made up of three volumes and its primary objective was to refute Gnosticism.

He is believed to have been a hearer of Polycarp who was John's disciple and they both came from the same town. In his writings he quotes from more than 21 New Testament books including the four Gospels. During his time, Christians differed as to which gospels they preferred, Irenaeus asserted that four Gospels, Matthew, Mark, Luke, and John, were canonical scripture.Nothing is known of the date of his death, which must have occurred at the end of the 2nd or the beginning of the 3rd century. The Roman Catholic Church celebrates him as a martyr

Soli Deo Gloria


  1. 1. ^ Eusebius of Caesarea, Ecclesiastical History Bookv. Chapter v.
  2. 2. ^ Tertullian, De Carne Christi, 173.
  3. ^ Encyclopaedia Britannica: Saint Irenaeus(
  4. 4. ^ Eusebius, Historia 10. Ecclesiastica 5.4.1)
  5. 5. ^ Irenaeus, Against Heresies,, ^ Against Heresies 1.13.77.
  6. ^ Eusebius, Historia Ecclesiastica 5.24.1ff