in the Vescovado. He set to work upon the task and brought it to such a successful completion, introducing the Pope's portrait from life both in marble and in painting, that it was considered to be the best work which he had ever produced. Margaritone then set to work to complete the Vescovado, following the design of Lapo, and he displayed great activity; but he did not complete it, for a few years later, in 1289, war broke out again between the Florentines and Aretines, through the fault of Guglielmo Ubertini, bishop and lord of Arezzo, aided by the Tarlati of Pietramela and by the Pazzi of Val d'Arno, when all the money left by the Pope for the building of the Vescovado was expended upon the war, while evil befell the leaders, who were routed and slain at Campaldino. The Aretines then ordained that the tolls paid by the surrounding country, called a _dazio_, should be set aside for the use of the building, and this toll has lasted to our own day. To return to Margaritone, he seems to have been the first, so far as one can judge by his works, who thought it necessary to take precautions, when painting on wood, that the joints should be secure, so that no cracks or fissures should appear after the completion of the painting, and it was his practice to cover the panel completely with canvas, fastened on by a strong glue made of shreds of parchment and boiled in the fire; he then treated the surface with gypsum, as may be seen in many of his own pictures and in those of others. Over the gypsum, thus mixed with the glue, he made lines and diadems and other rounded ornaments in relief; and it was he who invented the method of grounding in bol-ar-moniac, on which he laid gold leaf which he afterwards burnished. All these things which had never been seen before may be noticed in his works, especially in an antependium in the Pieve of Arezzo, which contains scenes from the life of St Donate, and also in S. Agnesa and S. Niccolo in the same city.