Today is also the optional memorial of Saints Peter and Marcellinus, martyrs of the last great Roman persecution.

Marcellinus was a priest, and Peter an exorcist, both of the clergy of Rome, and eminent for their zeal and piety. In the persecution of Dioclesian, about the year 304, they were condemned to die for their faith.

You’ll find the rest of their story at EWTN.

UPDATE: Jeff Ziegler of the Ziegler A List also provides this link:
— The Catacomb of SS. Marcellinus and Peter.