York Minster's 600-year-old Great East Window has been rescued from a fire as it was undergoing restoration.
Fire crews and minster security staff spent the night moving more than 300 panels of stained glass as fire broke out at the minster stonemasons' yard.
About 30 firefighters were involved in the operation at the Minster Yard in Minstergate late on Wednesday night.
Thought to be the world's largest medieval window, it was completed in 1408 and has been valued at £27m.
It was removed from the east end of the minster in 2008 and its restoration is expected to take 10 years to complete.
The window is roughly the size of a tennis court and is described as the "Sistine chapel of the stained glass world" by the York Minster website.
It is the earliest piece of English art by a known artist, completed between 1405 and 1408 by John Thornton.
Wednesday night's salvage operation also involved moving stonemasons' templates and wooden carvings from the minster.
The Archbishop of York, Dr John Sentamu, visited the minister stoneyard on Thursday to survey the damage.
"I am glad to say that, apart from the two offices that were damaged, fire officers worked at such great speed that the damage was limited and no one was injured," he said.
" I am very grateful for the sterling efforts of the local fire service and the Minster Police in this regard.
"It was something of a shock for the stonemasons and glaziers who were returning to work today, but not a great deal of damage has been sustained to the building so for that we must be thankful."
A fire investigation officer examined the scene at the minster stoneyard
The Dean of York, the Very Revd Keith Jones, said: "Our first concern, after being ensured that no people were in danger, was for the precious things in store there. "Thanks to the prompt actions of our staff who worked with the fire brigade, they are safe.
"In a few days we shall know more about the cause and the consequences of the incident."
Fire investigation officers returned to the yard on Thursday to determine how the fire started.
Steven Wilkinson, head of the York Minster Police, said: "Thankfully the fire damage seems to have been limited to an office and store room on the first floor.
"We had to move the window, which was on the floor below, because of the risk of water damage."
The window panels have been temporarily moved to the nearby stonemasons' workshops and a neighbouring school hall.
Expert glaziers are now trying to identify a more secure storage facility.
In July 2009, the minster held a service to mark the 25th anniversary of a devastating fire which swept through the south transept, destroying part of the roof and damaging the famous 16th Century Rose Window.