Saint Erasmus served the Lord diligently from a young age. In his mature years, he was elevated to the rank of bishop of the city of Formia (Italy). During the persecution of Christians by the emperors Diocletian (284-305) and Maximian (284-305), Saint Erasmus left his diocese and retired to the Lebanese Mountains, where he hid for seven years. One day an angel appeared to him and said: "Erasmus! No one can defeat their enemies if they sleep. Go to your city, fight courageously and defeat your enemies." Listening to the Angel's voice, Saint Erasmus emerged from his solitude. 
The first people to ask him about his faith were the soldiers who were coming to meet him. Saint Erasmus confessed himself a Christian. He was brought to trial in Antioch before the Emperor Diocletian, before whom the saint fearlessly confessed his faith in Christ and boldly denounced the emperor of his impiety. Saint Erasmus was subjected to severe tortures, but remained steadfast. After being tortured, the saint was bound with iron chains and thrown into prison, from where he was miraculously led out by an Angel, saying: "Follow me, I will take you to Italy. You will lead many people there to salvation." 
In the city of Lycia, Saint Erasmus boldly preached to the people about Christ and resurrected the son of a noble man. After this miracle, 10,000 people were baptized in Lycia. The emperor of the Western half of the Roman Empire, Maximian Hercules, ordered the saint to be captured and brought to trial. Before this emperor, Saint Erasmus also boldly confessed his faith. He was beaten and threatened with crucifixion if he did not renounce Christ. Then they forced him to go to the idol temple, but when the saint entered, all the idols there fell and broke, and fire came out of the temple and burned many pagans. 
Remaining free, Saint Erasmus baptized many people, and then went to the city of Sirmium, where he was again captured and tortured. The saint was put in a red-hot furnace, but he remained alive and unharmed. This miracle so shocked those present that the emperor, fearing popular outrage, retired to his palace. The angel freed Saint Erasmus from his shackles and brought him to the city of Formia, that is, to his bishopric, where the saint baptized a multitude of people. 
The saint died there in 303. Christians honorably buried the remains of the holy hieromartyr.