Playlist :    • 1/4 Britains Most Fragile Treasure  
First broadcast: Oct 2011.
Historian Dr Janina Ramirez unlocks the secrets of a centuries-old masterpiece in glass. At 78 feet in height, the famous East Window at York Minster is the largest medieval stained-glass window in the country and it was the creative vision of a single artist, a mysterious master craftsman called John Thornton, one of the earliest named English artists.