Jewellery and other objects owned by the late Princess Margaret are being put up for auction by her children.
The princess wore the Poltimore Tiara on her wedding day
The money raised - expected to be about £3m - will be used to help pay off inheritance taxes on her estate.
The items on sale, including the tiara she wore on her wedding day, are going on public display ahead of the auction at Christie's in London next week.
Among the 800 pieces is a Faberge clock - a gift from Queen Mary - which is expected to fetch up to £800,000.
The Princess's children, Viscount Linley and Lady Sarah Chatto, have put the furniture, silver, works of art, jewellery and decorative objects up for auction on 13 and 14 June.
The Poltimore Tiara, created by Garrards in 1870 for Lady Poltimore and worn by the princess at her wedding to Lord Snowdon in 1960, is estimated to be worth between £200,000 and £300,000.
Princess Margaret, who died in 2002, was married to Lord Snowdon until 1978.
There have been reports that Lord Snowdon is unhappy that some of the items are being auctioned.
Christie's said there was no question of any of the pieces being withdrawn from the sale.
"This private matter has been resolved," said a statement from the auction house.
Among the lower value items is a gilt hedgehog brooch valued at just £50.
A five-row pearl and diamond Art Deco necklace worn by the Princess when she was photographed by Cecil Beaton for her 19th and 21st birthdays is expected to sell for up to £20,000.