After Donatello, most closely connected with the Medici, father and son, were two masters who, while fairly admitting the claims of the realistic principle, carried it out in a different spirit and in more ideal forms. Lorenzo Ghiberti, who finished the second door of the Baptistery in 1452, with the help of his son Vettorio, and in spite of his seventy-two years, undertook the commission for a third. He continued till the later years of Cosimo busily engaged on the rich silver reredos, in which Michelozzo, Verocchio, Bernardo Cennini, Antonio Pollaiuolo, and others, had a share. He also designed the great rose-window of Sta. Maria del Fiore, at which Francesco di Domenico Livi of Gambassi, who learned glass-painting in Germany, was working in 1436, and Bernardo di Francesco in 1443. Glass-painting in the true sense of the word was then just beginning to flourish; until that time coloured windows had been produced by simply putting variously tinted glass together in mosaic patterns. Many trod in the steps of Francesco Livi: notably Ser Guasparre da Volterra, who worked in the cathedral at Siena; while in Florence, Pisa, and Arezzo, the art was practised by the Jesuates of the order of the B. Giovanni Colombini, who were established in Florence in 1438, in the convent of San Giusto before Porta Pinti, and there built the great church which was pulled down in 1529. It was chiefly by them that Sta. Maria del Fiore, Sta. Croce, San Michele, and other buildings, were glazed with coloured windows.[138]