Here lies the bodies of Saints Marcellinus the priest and Peter the exorcist, who by a marvelous inspiration, with the help of the Lord, have brought many unbelievers to the knowledge of the true faith, have taught them the commandments of the law, and at last, by the command of the impious tyrant, have deserved to be crowned with the palm of martyrdom - Epitaph written by Pope Saint Damasus the first.

Marcellinus (a priest) and Peter (an exorcist) were both imprisoned during the persecution of Christians under the reign of Diocletian. Both Marcellinus and Peter embraced their suffering, seeing it as an opportunity for evangelization, and quickly converted majority of prisoners in jail with them—including the jailor and his entire family. This was accomplished when Peter set the daughter of the jailer free from an evil spirit which possessed her. Shortly thereafter, the jailor, his wife and their other children were baptised into the faith—right in the cell of Peter and Marcellinus. (AnaStPaul)