Sts. Mark and Marcellianus were twin brothers, of an illustrious family in Rome. They gave their lives for Christ in 286, under the persecutions of Diocletian, after suffering cruel torture. According to the Acta of St. Sebastian, Mark and Marcellianus, after having fearlessly confessed the Christian Faith in the midst of torments, were on the point of denying it after the tearful visit of their parents who came to visit them in prison. Thus we see how a great a danger to the souls of the Religious is to be found in unrestrained family affection.
(Adapted from The New Roman Missal by Father Lasance)