The crown of thorns is said to have been seized from Constantinople, the capital of the Roman Empire, during the Fourth Crusade - around A.D. 1200 - and was later sold to King Louis IX of France while he was in Venice.

King Louis kept the relic in the specially-built Saint Chapel and the thorns were broken off from the crown and given as gifts to people who married into the family.

The thorn at Stonyhurst College - a 400-year-old boarding school in Lancashire - was said to have been given to Mary Queen of Scots who married into the French royal family and she took it with her to Edinburgh.

After her execution in 1587, it was passed from her loyal servant, Thomas Percy, to his daughter, Elizabeth Woodruff, who then gave it to a Jesuit priest in 1600.

The priest brought it to the college and it has been kept at the Ribble Valley College ever since, the Daily Mail reported.

The thorn now is to be loaned to the British Museum for a new exhibition - "Treasures of Heaven" - inspired by saints, relics and devotion in medieval Europe.
The thorn has Mary Queen of Scots's pearls twined around it.

Jan Graffius, curator at Stonyhurst, said: "It is an incredible object and we are really delighted that it will form part of the British Museum exhibition. It is a priceless treasure."
The exhibition will open June 23 and run till Oct 9.