The Scriptural ordinance of the Lord's Supper had been supplanted by the idolatrous sacrifice of the mass. Papal priests pretended, by their senseless mummery, to convert the simple bread and wine into the actual "body and blood of Christ."--Cardinal Wiseman, The Real Presence of the Body and Blood of Our Lord Jesus Christ in the Blessed Eucharist, Proved From Scripture, lecture 8, sec. 3, par. 26.
With blasphemous presumption, they openly claimed the power of creating God, the Creator of all things. Christians were required, on pain of death, to avow their faith in this horrible, Heaven-insulting heresy. Multitudes who refused were given to the flames.¹
¹ For the doctrine of the mass as set forth at the Council of Trent see The Canons and Decrees of the Council of Trent in Philip Schaff, Creeds of Christendom, vol. 2, pp. 126-139, where both Latin and English texts are given. See also H. G. Schroeder, Canons and Decrees of the Council of Trent (St. Louis, Missouri: B. Herder, 1941). For a discussion of the mass see The Catholic Encyclopedia, vol 5, art. "Eucharist," by Joseph Pohle, page 572 ff.; Nikolaus Gihr, Holy Sacrifice of the Mass, Dogmatically, Liturgically, Ascetically Explained, 12th ed. (St. Louis, Missouri: B. Herder, 1937); Josef Andreas Jungmann, The Mass of the Roman Rite, Its Origins and Development, translated from the German by Francis A. Brunner (New York: Benziger Bros., 1951). For the non-Catholic view, see John Calvin, Institutes of the Christian Religion, b. 4, chs. 17, 18; and Edward Bouverie Pusey, The Doctrine of the Real Presence (Oxford, England: John H. Parker, 1855).