This window, glazed originally at the beginning of the fourteenth century, was enlarged and rebuilt with Perpendicular tracery in 1390-91 through the munificence of one of the canons, Henry Blakeborn; and in 1392 Robert Lyen, glazier, citizen of Exeter, and master glazier to the Cathedral, was commissioned to adapt the old glass to its new setting, adding what was necessary of his own work to fill the space. Robert Lyen's work is easily to be distinguished from the earlier work (which, besides that of 1302, includes four figures of about 1340-50, which he may have brought from other windows to fill up with). It consists of six figures, of which only three are under canopies of Lyen's time, and of a row, across the bottom, of short double-arched canopies enclosing coats of arms of past bishops of Exeter. The drawing is about equal to that of the Winchester School, but the canopies, with their multitude of crocketted pinnacles in strong outline, are far nearer to the regular Perpendicular type, such as we find at York, than anything that was being done by the Winchester School at that date. Was the work of Robert Lyen an example of a style which had become general throughout the west, and of which the influence extended as far as Coventry? For in 1405 John Thornton of Coventry was commissioned to fill with stained glass the huge east windows of the new choir of York Minster, and this is the earliest existing window, of which the date is known, in which the Perpendicular style in glass has taken definite form. [Illustration: PLATE XLIII HEAD, FROM ST. MICHAEL'S, SPURRIERGATE, YORK Fifteenth Century] [Sidenote: The east window of York Minster.] This great window is the glory of English stained glass. It is 78 feet high from top to bottom, and below the great mass of Perpendicular tracery, which fills the mighty pointed arch of it, there are the three tiers of lower lights divided by horizontal transoms, with nine lights in every tier. Each of these lights measures 3 feet 6 inches across, and is divided again by the thick iron frame-bars into roughly square panels, each of which contains a subject from the Bible. The canopy work which, in the hands of a fourteenth century artist, would have filled half the window space with its towering spires, is here reduced to a small many-pinnacled canopy just filling the head of each light (where it would have been an awkward shape for a subject), a narrow shafting forming a border down the side, and a very shallow flat arch dividing each subject from the one above. There has been no question here of eking out a poverty of ideas; on the contrary, the artist's aim seems rather to have been to get as much space as possible for the expression of them.