In the persecution under Diocletian, Sts. Severus, Serverianus, Carpophorus, and Victorinus, four brothers, were cruelly tortured until they expired in the hands of their tormentors. They were at first known simply as four Christians who had won the crown of martyrdom and continued to be so styled even after their names were learned.

(Source: The New Roman Missal, Rev. F. X. Lasance)