Giorgio Vasari

“ Moved by the entreaties of certain among his friends, Guglielmo had suffered himself, while still in his native country, to be present at a brawl, which resulted in the death of one who was their enemy, for which cause he was compelled to take the habit of a Monk in the order of San Domenico, as the sole means of escaping from the vengeance of 'the court and the pursuit of justice; but although he never abandoned the religious habit, thus assumed in France, he continued his studies in art nevertheless, pursuing them indeed until he had attained to the highest perfection. ”

“ Guglielmo possessed ample powers of invention, and there is great variety in the composition of his stories, which are exceedingly rich, the figures being well grouped and arranged; his works have contributed largely to enlighten those who came after him, as to the best methods of executing such paintings as are formed from pieces of glass; an undertaking which to all who have not much practice and dexterity, must needs appear to be an exceedingly difficult operation, as in fact it is. ”

“ As a man of religion, his habits were ever strictly regular, and the remorse of conscience which he suffered from having abandoned the Brotherhood in which he had taken orders, oppressed him greatly. Moved by this cause, he constructed a most beautiful window for the chapel of the High Altar in San Domenico, the Convent of his Order in Arezzo: on this he painted a Vine, which he figured as proceeding from the body of San Domenico, and whereon he depicted a vast number of monks, renowned for their sanctity: so that the whole represents the Tree of Religion. ”

“ Highly worthy of praise, therefore, is this excellent master, seeing that there is no one in that vocation who has effected so much as himself, whether we consider his powers of invention, design, colour, or the general excellence of the work. ”

“ The first work undertaken in Cortona by Guglielmo, was that part of the Cardinal’s palace which is turned towards the Piazza, and which the artist painted in chiaro-scuro, representing thereon the figure of Croton, with those of the other founders of that city. This being completed, the Cardinal, who perceived that Guglielmo was no less excellent as a man than distinguished as a master in art, then caused him to construct the window of the principal chapel in the capitular residence of Cortona, where the artist painted the Birth of Christ, with the Adoration of the Magi. ”

“ This master designed the pictures for bis windows with so good a method and order, that he brought the joinings of lead and iron, by which they are traversed in various parts, to arrange themselves among the conjunctions of his figures, and within the folds of their vestments, and this he did with so much skill, that they are not only never disadvantageously conspicuous, but are even made to lend a new grace to the painting; the pencil itself could not effect this object better, and thus the master has found means to turn a necessity into * a beauty and advantage. ”

“ It is difficult to imagine how the master has been able to arrange so many figures, all in the most appropriate attitudes, within so small a space, nor do we fail to perceive the expression of terror and amazement in that crowd of people at this awakening of the dead ”

“ In the three large vaultings he had represented the earlier events recorded in the beginning of the Old Testament, wherefore he afterwards depicted those related in the commencement of the New: [21] and what was herein effected by Guglielmo gives me reason to believe, that every man of genius who is determined to attain perfection, will be found to possess the power (if he will but endure the labour) of approaching those limits which have been set to the endeavours of men, in any science. ”

“ An old man, already divested of his clothing, is standing near in the act of taking off his shoes; angels are preparing the vestments of Christ, and above all is the Almighty Father, who sends down the Holy Spirit on his Son. This window is immediately over the baptismal font of the Cathedral, and in the same building the Prior Guglielmo painted a window whereon is represented the Resurrection of Lazarus, on the fourth day of his burial. ”

“ At a later period, considering within himself that the art of painting on glass could not secure a long duration to the works of those who attach themselves thereto, seeing that they are perpetually liable to destruction, Guglielmo conceived the desire of devoting himself to painting generally, and accordingly accepted a commission from the superintendents of works to the Episcopal church of Arezzo for the decoration in fresco of three very large vaultings, these being labours in which he hoped to leave an enduring memorial of his existence. ”

“ They are greatly extolled by those conversant in that art, and acquired for the artists good name and fame, no less than the advantages of gain.
But Maestro Claudio being very immoderate in eating and drinking, as is the custom of his nation, a practice which is an exceedingly dangerous one in the air of Rome, fell sick of a fever, and this became so violent, that in six days he departed to another life., Guglielmo was then left alone, and being deprived of his companion was almost as one lost. ”

“ Pastorino afterwards occupied himself with many branches of art, and among them, with the preparation of painting on glass, although he did not produce many works of that kind; Masso Porro, of Cortona, was also a zealous follower of the Priors method, but succeeded better in burning and joining the glass than in painting it. ”

“ By this process, the real or first colour is that which alone appears on the one side, whether it be red, blue, or green, while the other, which has about the thickness of the blade of a knife, or something more, remains white. There are many who from not having great practice or facility in the handling, do not use a point of iron for scaling the glass, because they fear to break the panes ”