It is evident from this notice that Spain was then unable to produce the finest quality of glass. With such as he brought with him from abroad, Henry engaged to fashion "every kind of figure, image, scroll, and other object whatsoever be commanded him, according to the place it is to fill; the colours of the glass to be well mingled and distributed." He was also to make "the leaden casings stout and deep, so as to embrace and hold the glass aforesaid, that it may resist the air and wind." In return for this, he was to be supplied with an erected scaffolding, with all the chalk and iron he might require, and with the proper number of assistants, receiving, in payment of his labour, one hundred and fifteen _maravedis_ for every square palm of glass the preparation of which should satisfy the superintendent and examiners of works. One of the witnesses to this document was Henry's wife, María Maldonada, who came forward to affix her signature "with the license and pleasure of the aforesaid Master Enrique, her husband." In 1433, Master Juan (perhaps the same as Joan de Arge, already mentioned) began to work at the windows of Burgos, where, later in this century, he was succeeded by Juan de Valdivieso and Diego de Santillana. We learn from the _Documentos Inéditos_ (pp. 159, 160) that Santillana lived at Burgos, and that, on May 31st, 1512, he contracted to make three "historical windows" for the monastery of San Francisco, at a price of ninety-five _maravedis_ for each palm of glass, this to be "of good colours and shades," and "measured by the Burgos standard." Two other contracts are preserved, signed by the same craftsman and both relating to Palencia. By one of them Santillana is to receive for six "storied windows," the subjects of which are specified, ninety-five _maravedis_ the palm, besides the scaffolding and his house and coals. Arnao de Flandes (Arnold of Flanders) was appointed master glass-painter to Burgos cathedral in 1512. Other glass-painters who worked here in the sixteenth century were Francisco de Valdivieso, Gaspar Cotin, Juan de Arce, his son Juan and grandson Pedro, and, in the seventeenth century, Valentin Ruiz, Francisco Alonso, Simon Ruiz, and Francisco Alcalde. Most of the windows made by all these men have been destroyed by time and weather, and have been replaced by barren panes of white; but a few fine specimens of the original work may yet be seen in the chapels of the Presentation, the Constable, and San Jerónimo. Perhaps the most remarkable of any is the rose-window, above the Puerta del Sarmental.[110]