The Catholic Encyclopedia agrees with them as to the severity of the persecutions. (The Fifth Seal, 303-313, pg. 34.)
“But the last persecution was even more severe than any of the previous attempts to extirpate Christianity. In Nicomedia ‘a great multitude’ were put to death with their bishop, Anthimus; of these some perished by the sword, some by fire, while others were drowned. In Egypt ‘thousands of men, women and children, despising the present life, . . . endured various deaths’ (Eusebius, Church History VII. 4 sqq.), and the same happened in many other places throughout the East. … But besides those who actually shed their blood in the first three centuries account must be taken of the numerous confessors of the Faith who, in prison, in exile, or in penal servitude suffered a daily martyrdom more difficult to endure than death itself. Thus, while anything like a numerical estimate of the number of martyrs is impossible, yet the meagre evidence on the subject that exists clearly enough establishes the fact that countless men, women and even children, in that glorious, though terrible, first age of Christianity, cheerfully sacrificed their goods, their liberties, or their lives, rather than renounce the faith they prized above all.”
Maurice Hassett, “Martyr,” The Catholic Encyclopdedia.