What was the first sovereign nation to accept Christianity as as state religion?
Some may think about Constantine I, who legalized Christianity in the Roman Empire in 313 AD. But he did not make it a state religion, or ban other religions. Quote: In 313 Constantine I and Licinius announced toleration of Christianity in the Edict of Milan, which removed penalties for professing Christianity (under which many had been martyred in previous persecutions of Christians) and returned confiscated Church property. However, it neither made paganism illegal nor made Christianity the state religion; these were later actions of the Byzantine Emperor Theodosius I.