Question

When did Christianity become the dominant religion in Europe?

just after the death of Christ
during the Middle Ages
during the 400s and 500s
during the twenty-first century

Answer 1

during the 400s and 500s

Explanation: Christianity became the dominant religion as the Roman Empire adopted it (Nicene Christianity was made the state church in 380) and throughout the 5th–6th centuries many Germanic kingdoms and peoples converted, so by the end of that period it was the primary religion across much of Europe.