At the same time Guglielmo made the round window for the façade of the Church of S. Francesco, a great work, in which he represented the Pope in Consistory, with the Conclave of Cardinals, and S. Francis going to Rome for the confirmation of his Rule and bearing the roses of January. In this work he proved what a master of composition he was, so that it may be said with truth that he was born for that profession; nor may any craftsman ever think to equal him in beauty, in abundance of figures, or in grace. There are innumerable windows executed by him throughout that city, all most beautiful, such as the great round window in the Madonna delle Lacrime, containing the Assumption of Our Lady and the Apostles, and a very beautiful window with an Annunciation; a round window with the Marriage of the Virgin, and another containing a S. Jerome executed for the Spadari, and likewise three other windows below, in various parts of the church; with a most beautiful round window with the Nativity of Christ in the Church of S. Girolamo, and another in S. Rocco. He sent some, also, to various places, such as Castiglione del Lago, and one to Florence for Lodovico Capponi, to be set up in S. Felicita, where there is the panel by Jacopo da Pontormo, a most excellent painter, and the chapel adorned by him with mural paintings in oils and in fresco and with panel-pictures; which window came into the hands of the Frati Ingesuati in Florence, who worked at that craft, and they took it all to pieces in order to learn how it was made, removing many pieces as specimens and replacing them with new ones, so that in the end they made quite a different window.
He also conceived the wish to paint in oils, and for the Chapel of the Conception in S. Francesco at Arezzo he executed a panel-picture wherein are some vestments very well painted, and many heads most lifelike, and so beautiful that he was honoured thereby ever afterwards, seeing that this was the first work that he had ever done in oils.
The Prior was a very honourable person, and delighted in agriculture and in making alterations in buildings; wherefore, having bought a most beautiful house, he made in it a vast number of improvements. As a man of religion, he was always most upright in his ways; and the remorse of conscience, on account of his departure from his convent, kept him sorely afflicted. For which reason he made a very beautiful window for the Chapel of the High-altar in S. Domenico, a convent of his Order at Arezzo; wherein he depicted a vine that issues from the body of S. Dominic and embraces a great number of sanctified friars, who constitute the tree of the Order; and at the highest point is Our Lady, with Christ, who is marrying S. Catherine of Siena—a work much extolled and of great mastery, for which he would accept no payment, believing himself to be much indebted to that Order. He sent a very beautiful window to S. Lorenzo in Perugia, and an endless number of others to many places round Arezzo.
And because he took much pleasure in matters of architecture, he made for the citizens of that country a number of designs of buildings and adornments for their city, such as the two doors of S. Rocco in stone, and the ornament of grey-stone that was added to the panel-picture of Maestro Luca in S. Girolamo; and he designed an ornament in the Abbey of Cipriano d' Anghiari, and another for the Company of the Trinità in the Chapel of the Crocifisso, and a very rich lavatory for the sacristy; which were all executed with great perfection by the stone-cutter Santi.
Finally, ever delighting in labour, and continually working both winter and summer at his mural painting, which breaks down the healthiest of men, he became so afflicted by the damp and so swollen with dropsy, that his physicians had to tap him, and in a few days he rendered up his soul to Him who had given it. First, like a good Christian, he partook of the Sacraments of the Church, and made his will. Then, having a particular devotion for the Hermits of Camaldoli, who have their seat on the summit of the Apennines, twenty miles distant from Arezzo, he bequeathed to them his property and his body, and to Pastorino da Siena, his assistant, who had been with him many years, he left his glasses, his working-instruments, and his designs, of which there is one in our book, a scene of the Submersion of Pharaoh in the Red Sea.
This Pastorino afterwards applied himself to many other fields of art, and also to glass windows, although the works that he produced in that craft were but few. Guglielmo was much imitated, also, by one Maso Porro of Cortona, who was more able in firing and putting together the glass than in painting it. One of the pupils of Guglielmo was Battista Borro of Arezzo, who continues to imitate him greatly in the making of windows; and he also taught the first rudiments to Benedetto Spadari and to Giorgio Vasari of Arezzo.
The Prior lived sixty-two years, and died in the year 1537. He deserves infinite praise, in that by him there was brought into Tuscany the art of working in glass with the greatest mastery and delicacy that could be desired. Wherefore, since he conferred such great benefits upon us, we also will pay him honour, exalting him continually with loving and unceasing praise both for his life and for his works.