My object in writing this work is to prove that the Roman Catholic Church is the only true one among so many other Churches, and to show how carefully the Almighty guarded her, and brought her victoriously through all the persecutions of her enemiesI think the History of Heresies is a most useful study, for it shows the truth of our Faith more pure and resplendent, by showing how it has never changed; and if, at all times, this is useful, it must be particularly so at present, when the most holy maxims and the principal dogmas of Religion are put in doubt : it shows, besides, the care God always took to sustain the Church in the midst of the tempests which were unceasingly raised against it, and the admirable manner in which all the enemies who attacked it were confounded. The History of Heresies is also useful to preserve in us the spirit of humility and subjection to the Church, and to make us grateful to God for giving us the grace of being born in Christian countries; and it shows how the most learned men have fallen into the most grievous errors, by not subjecting themselves to the Church's teaching.I will now state my reasons for writing this Work; some may think this labour of mine superfluous, especially as so many learned authors have written expressly and extensively the history of various heresies, as Tertullian, St. Ir#65533;neus, St. Epiphanius, St. Augustine, St. Vincent of Lerins, Socrates, Sozymen, St. Philastrius, Theodoret, Nicephorus, and many others, both in ancient and modern times. This, however, is the very reason which prompted me to write this Work; for as so many authors have written, and so extensively, and as it is impossible for many persons either to procure so many and such expensive works, or to find time to read them, if they had them, I, therefore, judged it better to collect in a small compass the commencement and the progress of all heresies, so that in a little time, and at little expense, any one may have a sufficient knowledge of the heresies and schisms which infected the Church. I have said in a small compass, but still, not with such brevity as some others have done, who barely give an outline of the facts, and leave the reader dissatisfied, and ignorant of many of the most important circumstances. I, therefore, have studied brevity; but I wish, at the same time, that my readers may be fully informed of every notable fact connected with the rise and progress of, at all events, the principal heresies that disturbed the Church.