Aksum Adopts Christianity
Aksum, in the Ethiopian highlands, controlled the Red Sea trade between Rome and India, minted its own gold coinage, and raised carved stone obelisks over a hundred feet tall. Its king converted to Christianity in the 330s — within a few years of Rome doing the same, and independently of it. The church he founded still exists: Ethiopian Orthodox Christianity has run continuously for seventeen centuries, survived the Islamic expansion that surrounded it, and remains the faith of tens of millions. It is one of the oldest state religions on earth, in a country that was never colonized.
A belief system rises, spreads, institutionalizes, and then schisms — changing the rules people accept as legitimate.