After the splendid outburst of painting in the first half of the fourteenth century, there came a lull. The thoughts and sentiments of mediaeval Italy had been now set forth in art. The sincere and simple style of Giotto was worked out. But the new culture of the Revival had not as yet sufficiently penetrated the Italians for the painters to express it; nor had they mastered the technicalities of their craft in such a manner as to render the delineation of more complex forms of beauty possible. The years between 1400 and 1470 may be roughly marked out as the second period of great, activity in painting. At this time sculpture, under the hands of Ghiberti, Donatello, and Luca della Robbia, had reached a higher point than the sister art. The debt the sculptors owed to Giotto, they now repaid in full measure to his successors, in obedience to the law whereby sculpture, though subordinated, as in Italy, to painting, is more precocious in its evolution. One of the most marked features of this period was the progress in the art of design, due to bronze modelling and bas-relief; for the painters, labouring in the workshops of the goldsmiths and the stone-carvers, learned how to study the articulation of the human body, to imitate the nude, and to aim by means of graduated light and dark at rendering the effect of roundness in their drawing. The laws of perspective and foreshortening were worked out by Paolo Uccello and Brunelleschi. New methods of colouring were attempted by the Peselli and the Pollajuoli. Abandoning the conventional treatment of religious themes, the artists began to take delight in motives drawn from everyday experience. It became the fashion to introduce contemporary costumes, striking portraits, and familiar incidents into sacred subjects, so that many pictures of this period, though worthless to the student of religious art, are interesting for their illustration of Florentine custom and character. At the same time the painters began to imitate landscape and architecture, loading the background of their frescoes with pompous vistas of palaces and city towers, or subordinating their figures to fantastic scenery of wood and rock and seashore. Many were naturalists, delighting, like Gentile da Fabriano, in the delineation of field flowers and living creatures, or, like Piero di Cosimo, in the portrayal of things rare and curious. Gardens please their eyes, and birds and beasts and insects. Whole menageries and aviaries, for instance, were painted by Paolo Uccello. Others, again, abandoned the old ground of Christian story for the tales of Greece and Rome; and not the least charming products of the time are antique motives treated with the freshness of romantic feeling. We look in vain for the allegories of the Giottesque masters: that stage of thought has been traversed, and a new cycle of poetic ideas, fanciful, idyllic, corresponding to Boiardo's episodes rather than to Dante's vision, opens for the artist.