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)
That this Octave dates only from the time of the Renaissance can be deduced from the fact that there is no special Mass for it in the Missal. And that the Roman Sacramentaries only mark today as that feast of the Crowned Saints. It is well to repeat, on account of the modern tendency to multiply octaves, that originally the celebration of the Octave was a characteristic of the Paschal solemnity.