The St. Edward's Crown has been moved to an undisclosed location for modification in preparation for the coronation of King Charles III next year, Buckingham Palace said on Saturday.
The 17th-century crown is the centerpiece of the Crown Jewels, displayed at the Tower of London and annually visited by more than a million visitors.
The crown has a purple velvet cap with an ermine band and is encrusted with rubies, amethysts, sapphires, garnet, topazes and tourmalines. It is just over 30 cm (12 inches) long and has a 2.23-kilogram (4.9-pound) solid gold frame.
The history of the crown
Versions of St. Edward's Crown are believed to have been used by monarchs since the 11th century. The current version was made for Charles II in 1661 as a replacement for the original, which was melted down in 1649 after the House of Commons abolished the monarchy and declared a commonwealth during the English Civil War.
The original is believed to have dated back to Edward the Confessor, who reigned in 1042-1066.
The crown was last worn by Queen Elizabeth II at her coronation in 1953. It will now be worn by King Charles III at his coronation on May 6. He will only wear it at the moment he is crowned.
After the coronation, Charles will wear the Imperial State Crown, created in 1937 for the coronation of King George VI.
The coronation takes place a few months after the ascension of a new sovereign, after a period of mourning and preparations.
Charles became the reigning monarch after his mother, Queen Elizabeth II, passed away on September 8. She reigned for 70 years.
Charles also became head of state of 14 Commonwealth countries, such as Australia, Canada and New Zealand. He has reportedly requested a less lavish ceremony due to concerns about public perception.