By Prof. Giovanni Pellegrino and Prof. Ermelinda Calabria
Christianity is one of the most widespread religions in the world and, throughout its history, has been the victim of oppression—oppression that, unfortunately, continues even today in the 21st century.
During the reign of Diocletian, the most brutal persecution ever carried out in the Roman Empire took place, specifically between 284 and 305 AD.
Initially, the Christian community was seen as an illegal secret society. While Christians distanced themselves from public office, interest in Christianity began to grow within families.
In the earliest years of Christianity, the Jewish authorities in Jerusalem fought against it, attempting in every way to prevent its preaching. As a result, repression spread increasingly throughout the Roman Empire, eventually leading to full-scale persecutions.
Let us now consider the persecutions that occurred before Diocletian.
The most savage persecution of all was that unleashed by Nero in 64 AD.
In 202 AD, Emperor Septimius Severus issued an edict forbidding conversion to Christianity and Judaism.
Between 235 and 238, Maximinus Thrax persecuted Christian leaders.
From 249 to 251, Decius continued the persecution. Subjects had to prove they were not Christians by offering sacrifices to the gods; otherwise, they were arrested, tried, and executed.
In 258, Valerian issued a new edict that imposed exile and forced labor in the mines as punishment.
In 260, Gallienus issued the first imperial edict of tolerance toward Christians, which led to nearly 40 years of peaceful coexistence.
In 303 AD, Diocletian, Maximian, Galerius, and Constantius Chlorus issued edicts aimed at revoking Christians’ legal rights and requiring them to conform to traditional Roman religious practices.
Emperors Decius, Valerian, and Diocletian, driven by political motives, ordered increasingly harsh persecutions, which ultimately failed to achieve their intended goals.
Christians were accused of sacrilege for refusing to worship the gods and were thus seen as a threat to the Pax Deorum and the emperor.
Roman oppression ended in 313 thanks to Emperor Constantine.
We will now focus on the persecution under Diocletian—the harshest in the history of his reign.
Diocletian began his campaign of persecution within the first 15 years of his rule.
Diocletian, or Gaius Valerius Diocles, was a Dalmatian soldier born into a humble family. He became a Roman army officer during the reign of Emperor Numerian, and upon Numerian’s death, he was proclaimed emperor by his troops.
One of Diocletian’s primary goals was to reorganize the empire. Since such a vast empire could not be governed by one man alone, in 286 he appointed a capable general from Pannonia, Maximian, as co-emperor.
He entrusted Maximian with the governance of the West, while retaining control of the Eastern part of the empire—the wealthier and more populous region—for himself.
In 293, he introduced a new form of government known as the Tetrarchy, in which power was divided between two emperors called Augusti—Maximian and Diocletian—each assisted by a Caesar designated as successor. Diocletian chose the Illyrian general Galerius, while Maximian selected Constantius Chlorus.
After twenty years of rule, the two emperors were to abdicate and hand power to the Caesars, in order to avoid dynastic struggles.
To be closer to the most exposed regions, each tetrarch chose a different city as their residence and capital: Diocletian in Nicomedia (Asia Minor), Maximian in Milan, Galerius in Sirmium, and Constantius in Trier on the Rhine frontier.
Within this Tetrarchy, Diocletian assumed the dominant role, and together they launched the final persecution against Christians, who were accused of threatening imperial authority and causing social disintegration.
Christianity was considered a religion that opposed the empire and distracted citizens from the worship of traditional deities.
Unlike Aurelian, Diocletian did not promote the cult of his own person but aligned himself with the Pantheon and the pagan gods. He associated himself with Jupiter, the head of the Pantheon, and initially showed tolerance toward Christians. Galerius, on the other hand, identified with Hercules, and both emperors were objects of adoratio: every person in their presence had to prostrate themselves.
Unfortunately, it was Galerius—co-emperor and a staunch pagan, son of a pantheistic priestess under Emperor Decius—who later fueled Diocletian’s hatred toward Christians.
Diocletian banned Christians from holding administrative and military positions in an effort to appease the gods.
When the oracle of Apollo confirmed the presence of “evil on earth,” Christians were conveniently made the scapegoats. Thus began the persecution. In 303, Galerius decided to act against them. Lactantius describes him as a brutal man, full of cruelty and fanatical hatred toward Christians.
After the second phase of persecution, it ended only in 311, when Galerius, on his deathbed, accused Christians of misunderstanding his true intentions and blamed them for his suffering. He ultimately begged them to pray to God for him.
On February 23, 303, Diocletian issued his first edict, drafted at Galerius’s suggestion: to burn the Holy Scriptures and destroy churches. For Galerius, this was a pretext to eliminate Christians infiltrated in the ruling class and the Church as an institution.
The persecution began with extreme ferocity on February 23, 303, starting in the East, where Christianity was most widespread. The first edict was posted in Nicomedia, and within days, Diocletian’s palace and chambers were set on fire twice. Feeling threatened, he abandoned all restraint and became increasingly ruthless.
This edict was followed by a second, which imposed harsher penalties, especially on public officials and all believers. Most Christians fled, and pagans remained indifferent.
Their suffering only strengthened the resolve of the faithful. Diocletian believed it was his duty to restore peace to the empire by establishing an absolute monarchy, adopting features of Eastern monarchies—such as the divine origin of the sovereign.
The second edict called for the arrest of “church leaders,” essentially the entire ecclesiastical hierarchy. Historian Eusebius recounts that prisons were so full they had to release common criminals.
The third edict, issued on November 20, 303, granted general amnesty: any priest would be released if he agreed to offer a sacrifice to the gods. The goal was to force Christians to renounce their faith and divide the community.
The fourth and final edict was made public at the beginning of 304 AD. Christians were required to gather and perform a collective sacrifice; refusal meant execution. The persecution continued until Diocletian’s abdication on May 1, 305, alongside Maximian, and ended definitively with the Edict of Milan, through which Constantine, in 313 AD, granted freedom of worship to all citizens—including Christians.
It is estimated that the persecutions caused the deaths of around 3,500 Roman citizens, in addition to many others who were persecuted, arrested, and tortured.
With this, we conclude our discussion on the persecutions unleashed by Diocletian.