In 1401, the first year of the fifteenth century, the competition was announced for the second gates of the Baptistery, which marks the beginning of Renaissance sculpture; and the same year witnessed the birth of Masaccio, who, in the words of Leonardo da Vinci, "showed with his perfect work how those painters who follow aught but Nature, the mistress of the masters, laboured in vain," Morelli calls this Quattrocento the epoch of "character"; "that is, the period when it was the principal aim of art to seize and represent the outward appearances of persons and things, determined by inward and moral conditions." The intimate connection of arts and crafts is characteristic of the Quattrocento, as also the mutual interaction of art with art. Sculpture was in advance of painting in the opening stage of the century, and, indeed, influenced it profoundly throughout; about the middle of the century they met, and ran henceforth hand in hand. Many of the painters and sculptors, as, notably, Ghiberti and Botticelli, had been apprentices in the workshops of the goldsmiths; nor would the greatest painters disdain to undertake the adornment of a _cassone_, or chest for wedding presents, nor the most illustrious sculptor decline a commission for the button of a prelate's cope or some mere trifle of household furniture. The medals in the National Museum and the metal work on the exterior of the Strozzi Palace are as typical of the art of Renaissance Florence as the grandest statues and most elaborate altar-pieces. [Illustration: IN THE SCULPTORS' WORKSHOP BY NANNI DI BANCO (For the Guild of Masters in Stone and Timber)]