Among the most important, early Christian doctrinaires, was Irenaeus. Originally from Smyrna in Anatolia (modern Turkey), Irenaeus claimed to have been a student of Polycarp, who, he further claimed, had been a student of the apostle John. This is not confirmed anywhere else in Christian literature, except much later, when it was used to back up Irenaeus’ scriptural authority by those who quoted him.
That he was born and raised in Anatolia is not in doubt; we see this in his writing, both in his use of language and in his familiarity with Anatolian affairs. One thing which separates Irenaeus from many early Christian figures, is that he was, so far as we know, born into a Christian family; he did not convert as an adult. He traveled west and, according to tradition, was installed as Bishop of Ludunum (modern Lyon) by the Bishop of Rome. Christianity had not spread too far west, at that time, so it’s likely that this appointment simply meant that Irenaeus led a missionary expedition to the area.
In short order, Irenaeus ran up against a roadblock in his missionary efforts: the presence of Valentinians. These were Gnostic Christians who followed the teachings of the poet and sage Valentinus of Alexandria. A significant community of Valentinians had grown up in Rome, and apparently spread, from there, into southern Gaul (among other regions). There, as it had in northwestern Italy, it proved popular.
Irenaeus, stymied by this, decided to wage a theological and philosophical war on the Valentinians of his See. He preached widely against them, making little headway at first. He composed letters condemning Gnosticism generally and asking Gnostics to seek the “true faith,” but these fell mostly on deaf ears. Having been born in the faith, and taught Christianity from the cradle, Irenaeus had a powerful, innate sense of “orthodoxy”; the more resistance he encountered, the more fervently he reacted.
Having learned much from the few Gnostic converts he and his followers made, he wrote a long tome, now known as Adversus Haereses (“Against Heresies”). He wrote it originally in Greek, which — given that he lived in the Latin-speaking west — indicates he’d intended it for an eastern audience. Very likely he’d planned it as an appeal for assistance (in the form of missionaries of his own ilk, and of course donations) from what he considered more “traditional” Christians in the east.
A central problem Irenaeus encountered was to define specific criteria which delineated orthodox from non-orthodox Christianity. While he had his own sense of orthodoxy, he could not count on others’ ability to understand or uphold it. Worse, he feared his own followers might later be swayed by the Gnostics and drawn away (in fact, we cannot assume this didn’t happen). This became a central problem of A.H. After describing Gnostic doctrines as he understood them (of course, with a healthy dose of disapproving bias), he finally arrives at a solution: “Orthodox” Christianity must be both scriptural and apostolic. That is, it must be based on sacred writings, and originating with the Apostles themselves.
Of course, Irenaeus claimed this for his own teachings; he drew heavily on widely-respected Christian writings to support his positions, especially the gospels (he specified the four that we now consider canonical), and claimed Johannine pedigree for himself (via Polycarp as an intermediary). It’s no coincidence, then, that Irenaeus’ “scriptural and apostolic” distinction made him — in his own mind — the greatest authority on “orthodox” Christianity in the west.
Christian tradition holds that Irenaeus was martyred, but no accounts exist of this, not even of late or suspect origin. Of his late life we know little. We also do not know how well his missionary efforts worked out, since subsequent migrations and the persecutions of Diocletian, late in the 3rd century, have deprived us of information about the Christians who remained there. It is known, though, that Gnosticism persisted in the region, even if their numbers were small, since later Christian authors mention their continued presence in southern Gaul.
Of course, this is only to be expected. Despite the sporadic popularity of some Gnostic sects and the presence of some “orthodox” congregations, especially in Italy but also in Iberia (modern Spain) and northwestern Africa, Christianity remained far and away a minority religion in the western Empire. The situation was very different in the east, where Irenaeus had come from, which perhaps explains more than a little of his frustration.
Irenaeus’s lasting effect on Christianity was his generic principle of “scriptural and apostolic.” While he intended this notion to bolster his own definition of orthodoxy, and had meant it to be applied in particular manner, it’s fungible enough that it can be applied in varying ways. Ultimately it would come to be used against his very own Catholic Church, during the Reformation, as its practices, doctrines, and dogmas were re-examined under the microscope of Irenaeus’s variable specification.
↵ Go back up to Early Christian History menu.