St. Sebastian is a Roman Martyr during the persecution of Emperor Diocletian. Sebastian was most likely from Milan, Italy and was buried on the Via Appia, probably giving his name to the basilica of San Sabastino.

Sebastian served as an officer in the imperial guard under Emperor Diocletian until it was discovered that Sebastian followed the Christian Faith.

Sentenced to death, he was shot by archers from Mauretania. The arrows failed to kill him, and he was healed by Irene, widow of the martyr St. Castulus. Once fully recovered, Sebastian went before teh emperor who, after overcoming his shock at the miracle, commanded that Sebastian be clubbed to death.