While still a student, Calvin had shown that he possessed, besides a marvellous memory, an acute and penetrating intellect, with a great faculty for assimilating ideas and modes of thought; but he lacked what may be called artistic imagination,[185] and neither poetry nor art seemed to strike any responsive chord in his soul. His conduct was always straightforward, irreproachable, and dignified; he was by education and breeding, if not by descent, the polished French gentleman, and was most at home with men and women of noble birth. His character was serious, with little playfulness, little vivacity, but with a wonderful power of sympathy. He was reserved, somewhat shy, slow to make intimate friends, but once made the friendships lasted for life. At all periods of age, boy, student, man of letters, leader of a great party, he seems to have been a centre of attraction and of deferential trust. The effect of this mysterious charm was felt by others besides those of his own age. His professor, Mathurin Cordier, became his devoted disciple. Melanchthon wished that he might die with his head on Calvin's breast. Luther, in spite of his suspicion of everything that came from Switzerland, was won to love and trust him. And Knox, the most rugged and independent of men, acknowledged Calvin as his master, consulted him in every doubt and difficulty, and on all occasions save one meekly followed his counsels. He loved children, and had them at his house for Christmas trees; but (and this is characteristically French) always addressed them with ceremonious politeness, as if they were grown men and women deserving as much consideration as himself. It was this trait that captivated de Bèze when he was a boy of twelve. Calvin was a democrat intellectually and by silent principle. This appears almost everywhere in his private writings, and was noted by such a keen observer as Tavannes. It was never more unconsciously displayed than in the preface or dedication of the _Christian Institution_. "This preface, instead of pleading with the King on behalf of the Reformation, places the movement right before him, and makes him see it. Its tone throughout firm and dignified, calm and stately when Calvin addresses Francis I. directly, more bitter and sarcastic when he is speaking of theologians, _la pensée et la forme du style toutes vibrantes du ton biblique_, the very simplicity and perfect frankness of the address, give the impression of one who is speaking on equal terms with his peer. All suggest the Christian democrat without a trace of the revolutionary."[186] The source of his power--logic impregnated by the passion of conviction--is so peculiarly French that perhaps only his countrymen can fully understand and appreciate it, and they have not been slow to do so.