His birthplace was Thessalonica, and his parents were of noble origin. He was a brave warrior, respected for his wisdom and audacity. He built a brilliant career in the Roman army and civil service. He commanded the Roman forces in Thessaly and served as Proconsul of Hellas. Yet Demetrius had faith in Christ, and to him, it was dearer than all his worldly deserts. He preached God's truth and converted many Pagans by his word and personal example.
He lived during the reign of Emperor Maximian, a zealous persecutor of Christians. The emperor came to Thessalonica to celebrate the Roman victory over Scythians. During his visit, several resentful Pagans reported Demetrius to Maximian as a secret Christians. Maximian ordered to throw Demetrius into a dark and foul-smelling cell. But that did not shake Demetrius’ faith and devotion to the Lord.
Accompanying Emperor Maximian on his visit to Thessalonica was Lyaos, a barbarian of untold physical strength. He fought on stage on Pagan feasts for the amusement of the pagans, and no man who dared to challenge him survived the fight. Yet there was a young Christian named Nestor determined to show everyone that God was more powerful than any man. He went to see Demetrius in his cell to have his blessing. Demetrius made the sign of the cross over him and blessed him to fight the barbarian. Crying out 'God of Demetrius, help me!', he had a quick victory over Lyaios and killed him to the surprise of the onlookers. Enraged, Maximian killed Nestor with his sword and sent his men to kill Demetrius. Demetrius, servant Lupus, a Christian buried his master's remains with honour. Keeping his ring and tunic, he performed several miracles and healings with them. When news about the miracles reached Maximian, he ordered Lupus to be beheaded.
After Demetrius' martyrdom, myrrh flowed from his body, giving healing to many through the grace of God. For centuries, Demetrius has been venerated as the patron saint of Thessalonica.
Saint Seraphim’s life was marked by various signs and wonders testifying to his election from very early in life. At the age of seven Prokhor Moshnin (the birth name of the saint) fell from a tall bell tower but God delivered him unharmed.