To understand the history of William Penn we must have a clear idea of the Quaker faith in the time of Charles II. All through the Middle Ages the Christian Church, which was the Roman Catholic Church, had built up a network of beliefs that people took for granted, so that men never used their minds where religion was concerned, but were, to all intents and purposes, merely children, believing whatever the priests told them to believe. For centuries England, as well as all of Western Europe, had taken its creed directly from the Pope and his clergy, no more doubting the truth of what was told them than a child doubts the truth of the multiplication-table. But at length certain men of unusual independence of mind, men such as Martin Luther and John Calvin, became restless under the arbitrary teachings of the Pope and dared to question whether the priests were always right, no matter what they said. These men, and others like them, took part in what was known as the Reformation, an era in which men began to do a little thinking for themselves. The revival of the classical learning of Greece and Rome and the invention of the printing-press helped this new freedom of thought greatly. The first books to come from the printing-presses were copies of the Bible, which had formerly been beyond the reach of all but the priests, and as men soon translated the Scriptures from Latin into English and French and German and other languages, the people gradually became able to read the Old and New Testaments for themselves. The Bible was no longer a sealed book, from which the clergy gave the ordinary man and woman as much or as little as they thought good. It was free to all, and new teachers began to explain its meaning according to their own ideas. It took a long time, however, for men to break away from the implicit obedience they had given for centuries to the Church of Rome. The most daring reformers only rid themselves of one or two dogmas at a time. Wycliffe, the first great leader of the Reformation in England, only denied a part of the truth of the Mass, and kept almost all the rest of the Catholic belief. Huss, who followed him, only dared to doubt the truth of certain of the miracles, though he did declare that he believed in religious liberty. Martin Luther himself devoted most of his eloquence to attacking the sale of indulgences, which had been carried to great excess. Later he grew so bold as to oppose the authority of the Pope, but he still held to the larger part of the creed of the early Church.