Marcellinus was a priest and Peter was an exorcist, that is, someone authorized by the Church to deal with cases of demonic possession. They were beheaded during the persecution of Emperor Diocletian. Pope Damasus wrote an epitaph apparently based on the report of their executioner, and Constantine erected a basilica over the crypt in which they were buried in Rome. Numerous legends sprang from an early account of their death.
Hagiographies place them in 4th century Rome. They are generally represented as men in middle age, with tonsures and palms of martyrdom; sometimes they hold a crown each.
