Giovanni, who in the cloister of S. Spirito, where the arches of Gaddo and Taddeo are, painted the dispute of Christ with the doctors in the temple, the Purification of the Virgin, the Temptation of Christ in the wilderness, and the baptism of John, but after having given rise to the highest expectations he died. Cennino di Drea Cennini da Colle of Valdelsa also learned painting from Andrea. He was very fond of his art and wrote a book describing the methods of working in fresco, in tempera, in glue and in gum, and also how to illuminate and all the ways of laying on gold. This book is in the possession of Giuliano, goldsmith of Siena, an excellent master and fond of that art. The first part of the book deals with the nature of colours, both minerals and earths, as he had learned it of Agnolo his master. As he did not perhaps succeed in painting with perfection, he was at least anxious to know the peculiarities of the colours, the temperas, the glues and of chalks, and what colours one ought to avoid mixing as injurious, and in short many other hints which I need not dilate upon, since all these matters, which he then considered very great secrets, are now universally known. But I must not omit to note that he makes no mention of some earth colours, such as dark terra rossa, cinnabar and some greens in glass, perhaps because they were not in use. In like manner umber, yellow-lake, the smalts in fresco and in oil, and some greens and yellows in glass which the painters of that age lacked, have since been discovered. The end of the treatise deals with mosaics, with the grinding of colours in oil to make red, blue, green and other kinds of grounds, and with mordants for the application of gold but not at that time for figures. Besides the works which he produced with his master in Florence, there is a Madonna with saints by his hand under the loggia of the hospital of Bonifazio Lupi, of such style and colouring that it has been very well preserved up to the present day. In the first chapter of his book Cennino says these words in speaking of himself: "I, Cennino di Drea Cennini da Colle of Valdelsa, was instructed in this art for twelve years by Agnolo di Taddeo of Florence, my master, who learned the art of his father Taddeo, whose godfather was Giotto and who was Giotto's pupil for twenty-four years. This Giotto transmuted the art of painting from Greek into Latin, and modernised it, and it is certain that he gave more pleasure than any one else had ever done." These are Cennino's very words, by which it appears that as those who translate from Greek into Latin render a very great service to those who do not understand Greek, so Giotto, in transmuting the art of painting from a style which was understood by no one, except perhaps as being extremely rude, into a beautiful, facile, and smooth manner, known and understood by all people of taste who possess the slightest judgment, conferred a great benefit upon mankind.