Didascalicon, Book III: the art of study (discipline and method)
Chapter VII. What is necessary for students
Three things are necessary for students: nature, exercise, discipline. In nature it is considered that one easily perceive what is heard and firmly retain what is perceived. In exercise, that by labor and diligence one cultivate the natural sense. In discipline, that living laudably one compose morals with knowledge. Of these three we shall touch a little in each, by way of introduction.