Two of Robert Lyen's four surviving panels from 1391. Heraldry:

• Arms of King Henry IV or later (showing France modern);
• Arms of John de Grandisson, Bishop of Exeter 1327 to his death in 1369;
• Arms quarterly of four: 1&4: Montagu quartering Monthermer; 2&3: Neville (probably arms of George Neville (c. 1432 – 8 June 1476), archbishop of York and Chancellor of England, the youngest son of Richard Neville, 5th Earl of Salisbury, and Alice Montagu. He was the brother of Richard Neville, 16th Earl of Warwick, known as the "Kingmaker).
  

Left: St Sidwell, a female martyr carrying a scythe. Right: St Helen, holding the True Cross. The original window was erected Circa 1300, as a six light window. When the east end of the cathedral was rebuilt, it had 3 lights added. Glazed first by Master Walter of Rouen in 1304 , it suffered a large amount of masonry decay by the 1380s and had to be remade. The new design, completed in 1390, involved carrying four central mullions to the head of the window, and adding strength by securing them with transoms. In 1391 Robert Lyen of Exeter was commissioned to glaze the new window, resetting the surviving early 14th century glass and adding new panels where needed.

After the Reformation the window suffered some damage, losing several figures in its lowest and middle tiers. In the 18th century two restorations saw the introduction into the window of late medieval glass from elsewhere in the cathedral. Between 1894 and 1896 Frederick Drake, completely restored the east window glass. Between 1982 and 1986 the glass was conserved by Chapel Studios.

At the top and bottom of the window there are many coats of arms. Continuing down in the middle is: Abraham, Moses, and Isaiah. The row beneath this depicts Saint Sidwell (a female Saint of Devon), St Helen, an Archangel, St Michael, St Catherine, St Edward the Confessor, and St Edmund. The main figures of the window are: St Margaret, St Catherine, Mary Magdalene, St Barbara, The Virgin and Child, St Martin, St Peter, St Paul, and St Andrew.