St. Sebastian was a Roman martyr and little more than the fact of his martyrdom can be proved. In the “Depositiomartyrum” of the Chronologer of 354, it is mentioned that Sebastian was buried on the Via Appia in Rome. St. Ambrose states that Sebastian came from Milan and was venerated even there. Sebastian was an officer in the imperial bodyguard and had secretly done many acts of love and charity for his brethren in the Faith. When he was finally discovered to be a Christian in 286, he was handed over to the Mauretanian archers, who pierced him with arrows; he was healed, however, by the widowed St. Irene.

He was finally killed by the blows of a club. In 367, a basilica which was one of the seven chief churches of Rome was built over his grave. The present church was completed in 1611 by Scipio Cardinal Borghese. His relics, in part, were taken in the year 826 to St. Medard at Soissons. St. Sebastian is considered a protector against the plague. Celebrated answers to prayer for his protection against the plague are related of Rome in 680, Milan in 1575, and Lisbon in 1599. He is widely venerated among the Syro-Malabar Christians of central Kerala as the protector against famine, war and plagues.