Dionysius the Great was the 14th Pope and Patriarch of Alexandria from December 28, 248 until his death. Most information known about him comes from surviving correspondence.
He was called “the Great” by Eusebius, Basil of Caesarea and others. After St. Cyrpian, he was seen as the most eminent bishop of the third century.
Dionysius was born to a wealthy pagan family sometime in the late 2nd, or early 3rd century. He spent most of his life reading books and studying pagan rituals. . He converted to Christianity, as an adult, after he received a vision from God. In this vision he was commanded to study the heresies facing the Christian Church so that he could refute them with solid doctrine. After his conversion, he joined the Catechetical School of Alexandria. He studied from Origen and Pope Heraclas. He eventually became leader of the school and presbyter of the Christian church, succeeding Pope Heraclas in 231. Later he became Pope of the Coptic Orthodox Church of Alexandria & Patriarch of the See of St. Mark in 248 after the death of Pope Heraclas
During 249, a major persecution was carried out in Alexandria by a polytheist mob. Hundreds of Christians were assaulted, stoned, burned or cut down on account of their refusal to deny their faith. Dionysius managed to survive this persecution and the civil war after. In January 250, the new emperor Decius issued a decree of legal persecution. Many Christians were scared and denied their faith. They offered a token sacrifice, while others attempted to obtain false documents affirming their sacrifice. Others who refused to sacrifice faced public ridicule and shame among their family and friends. If authorities found them, they could expect brutal torture and execution. Many fled from the city to the desert, where most died from exposure, hunger, thirst, or attacks by bandits or wild animals.
Dionysius himself was pursued by the prefect Aurelius Appius Sabinus, who had sent out an assassin to murder him on sight. Dionysius spent three days in hiding before departing on the fourth night with his servants and other loyal followers. After a brush with a group of soldiers, he managed to escape with two of his followers, and set up a residence in the Libyan desert until the end of the persecution the following year.
He supported Pope Cornelius in 251. There had been a schismatic church set up with a hard position on the readmittance of Christians who had given in during the persecution. Dionysius ordered the Eucharist should not be refused to anyone who asked for it at the time of their death, even those who had been previously lapsed.
In 252 an outbreak of plague ravaged Alexandria. Dionysius, and other priests and deacons, assisted the sick and dying.
The persecutions subsided somewhat under Trebonianus Gallus, but renewed under Valerian who replaced Gallus. Dionysius was imprisoned and then exiled. When Gallienus, took over the empire he released all the believers who were in prison and brought back those in exile. Gallienus wrote to Dionysius and the bishops a letter to assure their safety in opening the churches. He died on March 22, 264.