He was born in the province of Asia, to a Scythian who had secretly converted to Christianity. Like his parents, he was a secret follower of Christ, serving as a legionary in the Roman army during the reign of the Emperor Decius. During a campaign, an Angel appeared to him, gave him a sword and told him to go into battle trusting in Christ's help. Mercurius plunged into battle, fought his way alone through the enemy lines, and reached the barbarian commander Rigas, whom he killed. Upon the death of their chief the barbarians scattered and the victory was won.
  The Emperor, hearing of the young soldier's exploits, promoted him to a position at court. There, lulled by the pleasures and honors of the court, Mercurius forgot his duties to Christ his King. One night the same Angel who had given him the sword appeared to him once again and reminded him of the sword that Christ had given him, an emblem of the battle of martyrdom that he was about to enter. The next day Mercurius, now returne