Key Dates in the Arian Controversy
- c. 318–319 AD: Arius, a presbyter in Alexandria, begins teaching that “there was a time when the Son was not,” challenging the doctrine of the Trinity.
- 321 AD: A council in Alexandria condemns Arius and his followers.
- 325 AD: First Council of Nicaea: Emperor Constantine convenes this council, which condemns Arianism and declares the Son is of the same essence (homoousios) as God the Father.
- 325–328 AD: Post-Nicaea instability: While Arius is exiled, supporters and opponents clash, leading to the temporary banishment of orthodox leaders like Athanasius.
- 337 AD: Death of Constantine; his successor, Constantius II, favors Arianism, leading to the temporary triumph of the movement.
- 340s–350s AD: Arianism spreads among the Goths, largely through the missionary work of Ulfilas.
- 357 AD: The Council of Sirmium produces a pro-Arian creed, often called the “Blasphemy of Sirmium”.
- 361–363 AD: Emperor Julian permits banished bishops to return, resulting in intense theological debates.
- 378 AD: Death of the pro-Arian Emperor Valens at the Battle of Adrianople, leading to a shift in favor of Nicene orthodoxy.
- 381 AD: Council of Constantinople: The Council explicitly condemns Arianism and upholds the Nicene faith, effectively marking the end of Arianism as a significant force within the Roman Empire.
- 5th–8th Century: Arianism persists among Germanic tribes (Goths, Vandals) outside the Roman mainstream before gradually disappearing.
