The Diocletianic Persecution (or Great Persecution) is the last and most severe persecution of Christians in the Roman empire.

In 303, the Emperors Diocletian, Maximian, Galerius and Constantius issue a series of edicts rescinding the legal rights of Christians and demanding that they comply with traditional Roman religious practices.

Later edicts target the clergy and demand universal sacrifice, ordering all inhabitants to sacrifice to the gods.

The persecution varies in intensity across the empire—weakest in Gaul and Britain, where only the first edict is applied, and strongest in the Eastern provinces.

Persecutory laws are nullified by different emperors at different times, but Constantine and Licinius's Edict of Milan (313) has traditionally marked the end of the persecution.Christians had always been subject to local discrimination in the empire, but early emperors were reluctant to issue general laws against them.

It was not until the 250s, under the reigns of Decius and Valerian, that such laws were passed.

Under this legislation, Christians were compelled to sacrifice to Roman gods or face imprisonment and execution.

After Gallienus's accession in 260, these laws went into abeyance.

Diocletian's accession in 284 did not mark an immediate reversal of disregard to Christianity, but it did herald a gradual shift in official attitudes toward religious minorities.

In the first fifteen years of his rule, Diocletian had purged the army of Christians, condemned Manicheans to death, and surrounded himself with public opponents of Christianity.

Diocletian's preference for activist government, combined with his self-image as a restorer of past Roman glory, presaged the most pervasive persecution in Roman history.

In the winter of 302, Galerius had urged Diocletian to begin a general persecution of the Christians.

Diocletian was wary, and asked the oracle of Apollo for guidance.

The oracle's reply was read as an endorsement of Galerius's position, and a general persecution is called on February 24, 303.Persecutory policies vary in intensity across the empire.

Where Galerius and Diocletian are avid persecutors, Constantius is unenthusiastic.

Later persecutory edicts, including the calls for universal sacrifice, are not applied in his domain.

His son, Constantine, on taking the imperial office in 306, restores Christians to full legal equality and returns property that had been confiscated during the persecution.

In Italy in 306, the usurper Maxentius ousts Maximian's successor Severus, promising full religious toleration.

Galerius ends the persecution in the East in 311, but it is resumed in Egypt, Palestine, and Asia Minor by his successor, Maximinus.

Constantine and Licinius, Severus's successor, signs the "Edict of Milan" in 313, which offers a more comprehensive acceptance of Christianity than Galerius's edict had provided.

Licinius ousts Maximinus in 313, bringing an end to persecution in the East.The persecution fails to check the rise of the church.

By 324, Constantine is sole ruler of the empire, and Christianity has become his favored religion.

Although the persecution results in the deaths of—according to one modern estimate—3,000 to 3,500 Christians, and the torture, imprisonment, or dislocation of many more, most Christians avoid punishment.

The persecution does, however, cause many churches to split between those who had complied with imperial authority (the traditores), and those who had remained "pure".

Certain schisms, like those of the Donatists in North Africa and the Meletians in Egypt, persist long after the persecutions.

The Donatists will not be reconciled to the Catholic Church until after 411.

In the centuries that follow, some Christians create a "cult of the martyrs", and exaggerate the barbarity of the persecutory era.

These accounts are criticized during the Enlightenment and after, most notably by Edward Gibbon.

Modern historians like G. E. M. de Ste.

Croix have attempted to determine whether Christian sources exaggerated the scope of the Diocletianic persecution.