The reason the Quakers absorbed many of the other sects and grew so rapidly, and doubtless the chief reason why they appealed so strongly to the liberal mind of young William Penn, was that they set forth as their aim the definite plan of returning to primitive Christianity in its simplest form. To those men and women who thought that all religion had become hopelessly corrupt through the ignorance and fraud and cruelty of the priesthood that had so long controlled the church, the Quaker leaders tried to show that original Christianity was as pure and simple as ever. What they wanted was that people should return to the doctrines of the Christian Church as they were before the Bishop of Rome became Pope, and before the priests interpreted the Bible as best suited themselves. The Quaker teachers declared that the Church of England and the Puritans had gone only halfway; they were still making their appeal chiefly to the rich and influential; this new religion was to satisfy the ordinary, the poor, the simple, those who cared little for wealth or high station. No wonder that this direct appeal made many converts among the great mass of English people, who were tired of the endless struggles between kings and parliaments, bishops and ministers. In their desire to return to the simplicity of the early days of the Christian Church, the Quakers became earnest students of those who were called the fathers of the Church,--the early writers on Christianity, such as Tertullian, Justin Martyr, Irenæus, Cyprian, and Origen. There they found the principles of a religious worship that was free from all elaborate ceremonies. There they found an absolute freedom of opinion; preachers who served without pay and solely because they felt spiritually called upon to preach; they also found that many of the early Christians were opposed to war and to the taking of oaths, and that they protested against the use of titles, elaborate clothes, and entertainments that tended to corrupt the tastes. Therefore it was easy for the Quaker leaders to show their audiences that the ideas they were urging upon them were actually the beliefs of the earliest Christians, and were therefore worthy of earnest consideration.