Silverware stolen from the British stately home of the former Viceroy of India Lord Curzon is of "priceless historical importance", officials say.
The National Trust charity says the stolen objects provide a unique insight into the Raj and are irreplaceable.
The artefacts, including a Burmese bowl, caskets and a wine cooler were stolen from Kedleston Hall.
They were acquired by the viceroy for the 1903 Delhi Durbar - the celebration to mark a royal coronation.
"These items are enormously important," said Simon McCormack, spokesman for the National Trust charity that owns the 18th Century neo-classical house.
Raiders broke into Kedleston Hall and took silver amassed by former owner Lord Curzon.
"They reflect a key period of Indian history during the last great flowering of the Raj in the early 20th Century - a key period of Indian history."
Mr McCormack said that among the items stolen were "civil society letters" stored in a silver casket which give a "fascinating insight" into how India was governed by Lord Curzon when he was Viceroy of India between 1889 and 1905.
"The items are in effect a time capsule of Victorian life in India - they show how the British Raj dealt with Indian administrators. They show how government in India was manifested at the time.
"The stolen items also reflect Lord Curzon's passion for Indian craftsmanship and architecture. The caskets for example were given to him when he organised the famous Delhi Durbar of 1903."
The Durbar was held to celebrate the coronation of King Edward VII and Queen Alexandra as Emperor and Empress of India.
Two full weeks of festivities were devised in meticulous detail by Lord Curzon in what was widely seen as a dazzling display of pomp, power and split-second timing.
The stolen objects were taken from the Eastern Museum at Kedleston Hall.
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