At the urging of the caesar Galerius, in 303 Diocletian began the last major persecution of Christians in the Roman Empire, resulting in the destruction of churches and the torture and execution of Christians who refused to sacrifice to the Roman gods.

Statistics. Statistics from Pew Research Center show that Christianity and Islam are persecuted in more countries around the world than other religions, and that Jews and Muslims are "most likely to live in countries where their groups experience harassment".

Modern historians estimate that during this period, known as the Diocletianic or Great Persecution and extending several years beyond the reign of Diocletian, as many as 3,000−3,500 Christians were executed under the authority of Imperial edicts.

The Romans protected the integrity of religions practiced by communities under their rule, seeing it as inherently correct to honor one's ancestral traditions; for this reason the Romans for a long time tolerated the highly exclusive Jewish sect, even though some Romans despised it.