One major problem with the Protestants is that their own divisions became more and more permanent. These divisions were increased by the arrival of Jean Calvin and Reformed Christianity on the scene as well as through the creation of official statements of faith and major Protestant treatises explaining them. Dr. John Rao shows that it was becoming clear that religious battles in the future would not just involve Catholics versus Protestants, but Protestants among themselves. Taken from: Protestant Rebellion and Catholic Reform (1517-1648) - 1997 Von Hildebrand Institute