As Leonardo grew older, he began to outstrip his master in the art of painting, though not in that of sculpture. At one time, it is said, Verocchio was working on a picture of the baptism of Jesus by John, in which an angel was represented as standing at one side. He entrusted the painting of this angel to his pupil. When the master came to look at the finished figure, he stood gazing in astonished silence. He was too true an artist not to feel that he and Leonardo had changed places, and that the boy's painting of the angel was worth all the rest of the picture. The story goes that Verocchio was so impressed by the feeling that he could only do badly what Leonardo could do perfectly that he never painted again.
One of the most interesting tales of the artist's boyhood tells of his painting of a shield. His father, Ser Piero, had gone to his country house outside of Florence. One evening a farmer of the neighborhood was brought to him as he sat in the garden, asking that he might speak with Ser Piero. He knew the farmer well, for they had often gone fishing together. "Well, what now, Francisco?" he asked, as the farmer came up bowing and bearing in his hands a wooden shield. Francisco explained that he had cut down a fig tree near his house, as it was too old to bear fruit, and that he had cut out of its wood the shield he was carrying. He had brought it to Ser Piero, hoping that the master would have the goodness to get it painted with some design, for he wished to hang it up in his kitchen as a remembrance of the old tree.
So when Ser Piero next went to Florence he took the shield to his son, not telling him to whom it belonged, but merely asking him to paint something on it. Leonardo, examining the piece of wood, found that it was rough and ill made, and that it would need much finishing before it would be possible to paint on it. So he held it before the fire till the fibres were softened and the crookedness straightened out, and then he planed and polished it. When it was all ready, he began to think about what the picture on it should be. A look of mischief came into his eyes.
"I know!" he said to himself. "A shield ought to have on it some frightful thing, so that the very sight of it may make the enemies of its wearer tremble. The person who sees this shield shall be as frightened as if he beheld the head of Medusa; only instead of being turned to stone, he will most likely run away." You see, he did not know that the shield was to adorn the home of a simple farmer.