He also at this time made a model for the cupola of Milan Cathedral, which was never carried out. In 1499 Leonardo left Milan and returned to Florence. He received a commission in 1503 to paint the wall at one end of the Council Hall of the Palazzo Vecchio, the decoration of the other end being at the same time entrusted to Michelangelo. Leonardo’s picture was never completed, and Michelangelo’s apparently never begun; but the cartoons for their two compositions, known respectively as the “Battle of the Standard” and the “Cartoon of Pisa,” excited the greatest admiration, and were termed by Benvenuto Cellini “the school of the world;” both have been lost or destroyed; all that we know of Leonardo’s composition is gained from a drawing of it by Rubens in black and red chalk in the gallery of the Louvre, to which, though spirited enough, he contrived to impart the coarse Flemish character with which all his work is disfigured. In 1514 Leonardo visited Rome, and was to have executed some work in the Vatican, had not an affront put upon him by the pope given him offence and caused him to leave Rome. He went to the King of France, Francis I., who was then at Pavia, took service with him, and accompanied him to France, in the early part of 1516. He was, however, weakened by age and in bad health, and did little or no new work in France. In a little more than three years’ time, in May 1519, he died, at Cloux, near Amboise, at the age of sixty-seven. Those pictures of Leonardo, which we may regard with confidence as the work of his own hand, fully justify the exceptional admiration with which he has always been regarded. He was excessively fastidious in his work, “his soul being full of the sublimity of art,” and spent years over the execution of some of his works. The painting of the portrait of Madonna Lisa is said to have extended over four years, and to have been then left incomplete. His mind also was at times equally bent on scientific matters, and for long periods he was entirely absorbed in the study of mathematics. For these reasons he produced but few pictures; if, however, he had left none, his drawings, which fortunately exist in large numbers, would suffice to account for the enthusiasm which his work has always excited. It is certain that we do not see his pictures in the state in which they left his easel; from some causes, unnecessary to discuss, they have blackened in the shadows, and the colors have faded. Vasari praises beyond measure the carnations of the Mona Lisa, which, he says, “do not appear to be painted, but truly flesh and blood;” but no trace of these delicate tints now remains. Leonardo was the author of many treatises, some of which only have been published. The most celebrated is the “Trattato della Pittura,” still a book of high authority among writings on art. MICHELANGELO BUONARROTI