The paintings of the period of the early Renaissance were usually frescoes; that is, they were painted directly upon the plaster walls of churches and sometimes of palaces. A few pictures, chiefly altar pieces, were executed on wooden panels, but it was not until the sixteenth century that easel paintings, that is, detached pictures on canvas, wood, or other material, became common. [Illustration: Relief by Niccola of Pisa from Pulpit at Pisa, showing Influence of Antique Models] [Sidenote: Giotto, 1266(?)-1337.] In the fourteenth century there was an extraordinary development in the art of painting under the guidance and inspiration of the first great Italian painter, Giotto. Before his time the frescoes, like the illuminations in the manuscripts of which we have spoken in a previous chapter, were exceedingly stiff and unlifelike. With Giotto there comes a change. Antique art did not furnish him with any models to copy, for whatever the ancients had accomplished in painting had been destroyed.[234] He had therefore to deal with the problems of his art unaided, and of course he could only begin their solution. His trees and landscapes look like caricatures, his faces are all much alike, the garments hang in stiff straight folds. But he aimed to do what the earlier painters apparently did not dream of doing--that is, paint living, thinking, feeling men and women. He was not even satisfied to confine himself to the old biblical subjects. Among his most famous frescoes are the scenes from the life of St. Francis,[235] a theme which appealed very strongly to the imagination of people and artists alike all through the fourteenth century. [Sidenote: Renaissance artists often practiced several arts.] Giotto's dominating influence upon the art of his century is due partly to the fact that he was a builder as well as a painter, and also designed reliefs for sculpture. This practicing of several different arts by the same artist was one of the striking features of the Renaissance period. [Sidenote: Italian art in the fifteenth century.] 125. During the fifteenth century, which is known as the period of the Early Renaissance, art in Italy developed and progressed steadily, surely, and with comparative rapidity, toward the glorious heights of achievement which it reached in the following century. The traditions of the Middle Ages were wholly thrown aside, the lessons of ancient art thoroughly learned. As the artists became more complete masters of their tools and of all the technical processes of their art, they found themselves ever freer to express in their work what they saw and felt. [Sidenote: Florence the art center of Italy.]