This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Tradition holds that King Tiridates the Third of Armenia, converted by Gregory the Illuminator, made Christianity the kingdom's official state religion in 301 CE, a full decade before Constantine's own toleration of the faith across the Roman Empire, with the Armenian church established at Vagharshapat. Modern scholarship treats the exact year as genuinely unresolved, uncertain whether it marks an early private royal conversion or a later public establishment made once toleration elsewhere had rendered open Christian rule politically safe.
Whichever year turns out to be correct, Armenia's standing as the first state anywhere to adopt Christianity as its official religion is the claim repeated as standard across the scholarly literature on the period, ahead of any Roman or other state establishment.
What this changed for Christianity's spread was the creation of the first officially Christian state in history, adopted from the top by a monarchy rather than spreading upward from converts within an existing pagan order. Gregory the Illuminator's conversion of Tiridates gave the new faith, for the first time anywhere, the backing of a whole kingdom's government behind it, a decade before any Roman emperor extended the faith so much as toleration, let alone official standing.