He determined to flee to England. How the flight failed, how the anger of the military commander, Frederick William, flamed up against the deserting officer, every one knows. With the days of his imprisonment in Küstrin and his stay in Ruppin, his years of serious education began. The terrible experiences he had been through had aroused new strength in him. He had endured, with princely pride, all the terrors of death and of the most terrible humiliation. He had reflected in the solitude of his prison on the greatest riddle of life--on death and what is beyond. He had realized that there was nothing left for him but submission, patience, and quiet waiting. But bitter, heart-rending misfortune is a school which develops not only the good--it fosters also many faults. He learned to keep his counsel hidden in the depth of his soul, and to look upon men with suspicion, using them as his instruments, deceiving and flattering them with prudent serenity in which his heart had no share. He was obliged to flatter the cowardly and vulgar Grumbkow, and to be glad when he finally had won him over to his side. For years he had to take the utmost pains, over and over again, to conquer the displeasure and lack of confidence of his stern father. His nature always revolted against such humiliation, and he tried by bitter mockery to give expression to his injured self-esteem. His heart, which warmed toward everything noble, prevented him from becoming a hardened egoist; but he did not grow any the milder or more conciliatory, and long after he had become a great man and wise ruler, there remained in him from this time of servitude some trace of petty cunning. The lion sometimes, in a spirit of undignified vengeance, did not scorn to scratch like a cat.