He was a Roman warrior and a Christian martyr, raised in a family of Scythians who were secret worshippers of Christ. He was in his twenties and serving in the Roman army when barbarians attacked Rome during the reign of Emperor Decius, a vicious persecutor of Christians. In a bloody battle, an angel appeared to him. He gave him a sword and commanded him to advance with it behind the enemy ranks without fear and kill the Barbarian commander. He followed the angel's command. The commander's demise undermined the fighting spirit of the Barbarians, the Romans won the war quickly, and Mercurius became a hero. Emperor Decius rewarded him with a high position at his court and made him his military advisor.
Yet Mercurius was not happy in his position. He was loyal to Christ, and he remembered the example of his grandfather, who suffered for Him, while he was dreading it. He felt too weak to renounce his riches and glory with the Emperor, unprepared to suffer for Christ, but also the duty to stand by Him, as he had won his victory wielding His sword.
A courtier had reported Mercurius to Emperor Decius as a secret Christian. Yet Decius loved his advisor, and would not act until he verified this information himself. He called Mercurius to His court for advice and offered him to pray to the idols together. Mercurius declined under a credible pretext. But when Decius summoned him again several days later, Mercurius panicked.
At that moment, the angel of God appeared to him again. He reminded him of the victorious sword, told him that he would endure torments for Christ, and would receive the gift of the Kingdom of Heaven. Boldly, Mercurius appeared before Emperor Decius, declared himself a Christian, renounced the awards and honours given to him, and suffered inhuman tortures before he was beheaded in Cappadocia, at twenty-five years of age.
The relics of Saint Mercurius acquired miracle-working powers, and even after his death, he continued to serve the other Christians as a soldier. Saint Basil once prayed before the icon of the Theotokos on which Saint Mercurius was painted with a sword, pleading the God to spare the Christians from the persecution promised to them by Julian the Apostate after his return from Persia. After his prayer, the depiction of Mercurius disappeared from the icon and eventually reappeared, with him holding a bloodied sword. According to legend, the Most Holy Theotokos had sent her warrior Mercurius to deliver the Christians from Julian the Apostate. At that moment, in Persia, Julian the Apostate died at the hand of an unknown soldier who quickly disappeared. Throughout the centuries, Christians have invoked the name of Saint Mercurius as they prayed for the Lord's protection from His enemies.
