Having considered, on the one hand, the excellent doctrines that the Council of Trent, with so much care and after so many diligent labors, taught against the errors of the heretics who infected the North; and having considered, on the other hand, that many of the matters debated in that Council—never sufficiently praised—though they had been diligently gathered by Cardinal Pallavicino, who composed its history, nonetheless in his work often lie scattered and confused: I therefore undertook, some years ago, the labor of collecting them and setting them down together, so that the reader might have the pleasure of seeing them all set distinctly before his eyes according to the order of each matter treated, and so might the more easily discover the sophisms of the heretics, and the better know the truths of our holy faith.
Many times I took up this work and laid it down again; but always, hindered by more pressing occupations, I was forced to interrupt it. At last, finding myself confined to my bed by a severe rheumatism that has seized almost my whole body, and does not permit me to rise or to go about the diocese as I formerly did, I have striven to bring to port the labor I had begun; and with the help of the Lord I have succeeded in seeing it completed, treating fully every point that came before me, and answering many other objections of the innovators of which Pallavicino made no mention. With this, moreover, it seemed good to me to treat of many other questions, dogmatic and scholastic, pertaining to the matters decided by the Council. I hope that the whole will prove right welcome to young students, and to all who love to know upon sound foundations the truths of our faith, and especially those that are most contested by the heretics.