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.
The East Window has been called England's Sistine Chapel. Within its 311 stained-glass panels is the entire history of the world, from the first day to the Last Judgment, and yet it was made 100 years before Michelangelo's own masterpiece. The scale of Thornton's achievement is revealed as Dr Ramirez follows the work of a highly-skilled conservation team at York Glaziers Trust. They have dismantled the entire window as part of a five-year project to repair centuries of damage and restore it to its original glory.
It's a unique opportunity for Dr Ramirez to examine Thornton's greatest work at close quarters, to discover details that would normally be impossible to see and to reveal exactly how medieval artists made images of such delicacy and complexity using the simplest of tools.
The East Window of York Minster is far more than a work of artistic genius, it's a window onto the medieval world and the medieval mind - telling us who were once were and who we still are, all preserved in the most fragile medium of all.