We now have, Paul says, a new map of the world ... by the time of the conversion of Constantine becomes the official religion of the Roman Empire. And even then, that's not a simple transformation.

Irene of Athens was the first Greek-Roman empress to wield power as a sole ruler of the Eastern Roman (Byzantine) Empire.

In 313 AD, the Emperor Constantine issued the Edict of Milan, which accepted Christianity: 10 years later, it had become the official religion of the Roman Empire.