What was the doubting? We are tempted in these days to think of intellectual difficulties, and Luther’s doubting is frequently attributed to the self-questioning which his contact with Humanism at Erfurt had engendered. But this idea, if not foreign to the age, was strange to Luther. His was a simple pious nature, practical rather than speculative, sensitive and imaginative. He could play with abstract questions; but it was pictures that compelled him to action. He has left on record a series of pictures which were making deeper and more permanent impression on him as the years passed; they go far to reveal the history of his struggles, and to tell us what the doubts were which drove him into the convent. The picture on the window in Mansfeld church of Jesus sitting on a rainbow, with frowning countenance and drawn sword in His hand, coming to judge the wicked; the altar-piece at Magdeburg representing a great ship sailing heavenwards, no one within the ship but priests or monks, and in the sea laymen drowning, or saved by ropes thrown to them by the priests and monks who were safe on board; the living picture of the prince of Anhalt, who to save his soul had become a friar, and carried the begging sack on his bent shoulders through the streets of Magdeburg; the history of St. Elizabeth blazoned on the windows of the church at Eisenach; the young Carthusian at Eisenach, who the boy thought was the holiest man he had ever talked to, and who had so mortified his body that he had come to look like a very old man; the terrible deathbed scene of the Erfurt ecclesiastical dignitary, a man who held twenty-two benefices, and whom Luther had often seen riding in state in the great processions, who was known to be an evil-liver, and who when he came to die filled the room with his frantic cries. Luther doubted whether he could ever do what he believed had to be done by him to save his soul if he remained in the world. That was what compelled him to become a monk, and bury himself in the convent. The lurid fires of Hell and the pale shades of Purgatory, which are the permanent background to Dante’s Paradise, were present to Luther’s mind from childhood. Could he escape the one and gain entrance to the other if he remained in the world? He doubted it, and entered the convent. § 3. Luther in the Erfurt Convent.