Query: During what century was the Roman conversion to Christianity considered complete?
Context: For much of the 4th century, Roman society stabilised in a new form that differed from the earlier classical period, with a widening gulf between the rich and poor, and a decline in the vitality of the smaller towns. Another change was the Christianisation, or conversion of the empire to Christianity, a gradual process that lasted from the 2nd to the 5th centuries.