In the persecution of Valerian, in the year 258, the proconsul of Africa, Galerius Maximus, went from Carthage to Utica, and commanded all the Christians who were detained in the prisons of that city to be brought before him. Saint Augustine says their number amounted to "more than one hundred and fifty-three" (Sermon 306), while Prudentius says they were about three hundred (Peristephanon 13).
The proconsul had ordered a great pit of burning lime to be prepared in a field, and by it an altar of idols with salt and hog’s liver placed on it ready for sacrifice. He caused his tribunal to be erected near this place in the open air, and he gave the prisoners their choice either to be thrown into this pit of burning lime, or to offer sacrifice to the idols which were set by it. They unanimously chose the first, with the encouragement of their bishop Kodratos, and were all consumed together in the furnace. Bishop Kodratos was put to death four days later.
Their ashes were afterwards taken out, and as they made up but one common mass cemented with the lime, these martyrs were called The White Mass or Massa Candida. Augustine however says: "They are called the Mass, after all, from their large numbers; called White from the splendor of their cause." And he exhorts: "So let us celebrate the festival of the Shining White Mass with shining white consciences. And as we follow in the footsteps of the martyrs, and keep our eyes fixed on the Head both of the martyrs and of ourselves, if we are really eager to attain to such a great good, let us not be afraid of a hard journey."