# Irenaeus writes Against Heresies (c. 180)

URL: https://christianity-history.com/timeline/180-irenaeus-writes-against-heresies
Location: Lugdunum, Gaul
Themes: Theology

Bishop Irenaeus of Lyon refutes Gnosticism and argues for apostolic succession and the four-Gospel canon. At this point in the timeline (c. 180), the Bishop of Rome was Pope Eleutherius (174/5 – 189). Dates for the earliest bishops of Rome are traditional and uncertain.

## Why it matters
Irenaeus writes Against Heresies mattered because it shaped how Christians understand God, Christ, salvation and the church.

Pope at the time: [Pope Eleutherius](https://christianity-history.com/popes/pope-eleutherius)

## Sources
- [Wikipedia — Irenaeus](https://en.wikipedia.org/wiki/Irenaeus)
- [Encyclopaedia Britannica topic lookup — Irenaeus writes Against Heresies](https://www.britannica.com/search?query=Irenaeus+writes+Against+Heresies)
- [Wikipedia — Early Church (period overview)](https://en.wikipedia.org/wiki/Ante-Nicene_period)