His parents, secret Christians, baptized Dimitri and instructed him in the faith. His father, the Roman proconsul, died when Demetrius reached adulthood. Emperor Maximian Galerius, who ascended the throne in 305, appointed Demetrius to replace his father as ruler and governor of the Thessalonian region. Demetrius' main duty was to defend his region from external enemies, but the emperor also demanded that he exterminate Christians. Instead, Demetrius began to eradicate pagan customs, and to convert pagans to the Christian faith.
Of course, the emperor was soon informed that Proconsul Demetrius was a Christian. Returning from a campaign against the Sarmatians (tribes inhabiting the Black Sea steppes), Maximian stopped in Thessalonica. Preparing for his death, Dimitri distributed his possessions to the poor, and he devoted himself to prayer and fasting. The emperor imprisoned the proconsul and began to entertain himself and the inhabitants of Thessalonica with gladiatorial battles in the circus. Christians were hunted down and dragged to the arena. Famous among the gladiators, the fervent Lius easily defeated the meek Christians in battle and, with the rejoicing of the savage crowd, threw them onto the spears of the soldiers.
The young man Nestor, a Christian, visited Demetrius in prison, and Demetrius blessed him for a single combat with Leah. Strengthened by God, Nestor defeated the proud gladiator and threw him onto the spears of the warriors. Nestor was supposed to be rewarded as the winner, but instead he was executed as a Christian.
By order of the emperor, the prison guards pierced Demetrius with spears in 306. The body of the Great Martyr Demetrius was thrown out to be devoured by animals, but the Thessalonians secretly buried it. Dimitri's servant Lupp took the bloody robe and the ring of the martyr and began to heal the sick with them. He was executed too. During the reign of Emperor Constantine the Great (324-337), a temple was erected over the grave of the Great Martyr Demetrius, and a hundred years later his incorruptible relics were found. Miracles and healings were performed at the tomb of the Great Martyr Demetrius. During the reign of Emperor Maurice, the Avars, who lived on the Don, besieged the city of Solun. Saint Demetrius appeared on the city wall, and the 100,000-strong army of the besiegers fled. Another time, the saint saved the city from famine. The life of Saint Demetrius tells us that he freed the captives from the yoke of the infidels and helped them reach Thessalonica.
Since the 7th century, fragrant and miraculous myrrh began to flow at the shrine of St. Demetrius, as contemporaries wrote. In the 14th century, Demetrius Chrysologus wrote about it: myrrh "is not water in its properties, but is thicker than it and does not resemble any of the substances known to us... It is more amazing than all incense, not only artificial, but also created by nature by God." For this reason, the Great Martyr Demetrius was called Myrrh-streaming.