Irenaeus in Wikipedia

Saint Irenaeus (Greek: Εἰρηναῖος), (2nd century AD – c. 202) was Bishop of Lugdunum in Gaul, then a part of the Roman Empire (now Lyons, France). He was an early church father and apologist, and his writings were formative in the early development of Christian theology. He was a hearer of Polycarp,[1] who in turn was a disciple of John the Evangelist. Irenaeus' best-known book, Adversus Haereses or Against Heresies (c. 180) is a detailed attack on Gnosticism, which was then a serious threat to the Church, and especially on the system of the Gnostic Valentinus.[2] As one of the first great Christian theologians, he emphasized the traditional elements in the Church, especially the episcopate, Scripture, and tradition.[2] Irenaeus wrote that the only way for Christians to retain unity was to humbly accept one doctrinal authority-episcopal councils.[3] Against the Gnostics, who said that they possessed a secret oral tradition from Jesus himself, Irenaeus maintained that the bishops in different cities are known as far back as the Apostles - and none of them were Gnostics - and that the bishops provided the only safe guide to the interpretation of Scripture.[4] His writings, with those of Clement and Ignatius, are taken to hint at papal primacy.[2] Irenaeus is the earliest witness to recognition of the canonical character of all four gospels...