23 Great and excellent is the martyrdom of Jesus. He surpassed in affliction and in confession all who were before or after. And after Him was the faithful martyr Stephen whom the Jews stoned. Simon (Peter) also and Paul were perfect martyrs. And James and John walked in the footsteps of their Master Christ. Also (others) of the apostles thereafter in various places confessed and proved true martyrs. And also concerning our brethren who are in the West, in the days of Diocletian there came great affliction and persecution to the whole Church of God, which was in all their region. The Churches were overthrown and uprooted, and many confessors and martyrs made confession. And (the Lord) turned in mercy to them after they were persecuted. And also in our days these things happened to us also on account of our sins; but also that what is written might be fulfilled, even as our Redeemer said:— These things are to be. The Apostle also said:— Also over us is set this cloud of confession; which (is) our honour, wherein many confess and are slain.
Source: Demonstrations (New Advent)