" That no one whatsoever should be denied freedom to devote himself either to the cult of the Christians or to such religion as he deems best suited to himself so that the highest divinity, to whos worship we pay allegiance with free minds, may grant us in all things his wonted favor and benevolence."
In 313 this was put into the Edict of Milan by Constantine to stop the persecution of the Christians. The Roman persecution of the Christians was pretty bad, probably as bad as the Christian's later slaughter of pagans and free thinkers.
After this was put into law, Christianity was a recognized religion. And for the next 200 years, ironically, they took it upon themselves to basically wipe out all the pagan cults.
The above is one small step for religious tolerance, one giant leap for wiping out the faiths that had lasted thousands of years.
