The traditional account, preserved mainly through later hagiography such as the Golden Legend and earlier Passio texts of uncertain date, presents Sebastian as an officer in the emperor Diocletian's guard, trusted enough to move freely among the court while concealing his Christian faith. He is said to have used this access to visit and encourage imprisoned Christians awaiting execution during the persecution, at one point converting the prison guard and his household, and even the Roman prefect Chromatius, according to the fuller versions of the story, though these later conversions are treated by historians as pious embellishment rather than confirmed fact.
When his faith was discovered, Diocletian, who is said to have valued him personally and felt betrayed by the concealment, ordered him bound to a stake or tree and shot by a company of archers, a punishment carried out by soldiers who had presumably served alongside him. The archers, according to the legend, left him for dead once he was covered with arrows and departed.
Sebastian's traditional dating places his death during Diocletian's persecution of Christians, though hagiographic sources vary on the exact year, some placing it as early as 288, which would put it before the emperor's formal empire-wide edicts against Christians began in 303. This atlas notes the tension rather than resolving it, since the surviving accounts are devotional narratives compiled well after the events rather than contemporary records.