The special Attic Sale will take place at the Guest Hall, at Alnwick Castle, from noon on Saturday, October 27.
Visitors will be able to bid for items from Alnwick Castle, Syon House (the Duke’s official London residence), Stanwick Hall, Albury Park and other Ducal properties.
By special invitation, there will also be items from Blagdon Hall, on the direction of Viscount Ridley.
In addition to everyday household objects such as lampshades, paintings, curtains, chairs and bookcases, a number of more unusual lots will go under the hammer.
These include a Regency rosewood and parcel gilt writing table, which was formerly in the Duchess’s sitting room at Alnwick Castle and is valued at £3,000 to £4,000.
A George IV rosewood and oak breakfront folio cabinet, which was supplied for the former music room at Syon House in 1827, is anticipated to sell for anything up to £10,000.
A marble relief, circa 1850, which features Cupid and Psyche, could fetch up to £12,000.
The Duke and Duchess have chosen to use local auction house, Anderson & Garland, and proceeds from the sale will be put towards the continuing programme of conservation of both collection and archive.
Viewings open at the Guest Hall and at Unit 13, Lionheart Enterprise Park North, in Alnwick, from 10am to 5pm, on Thursday, October 25, and Friday, October 26, and on the day of the sale from 10am to noon.
Those attending the auction do not need to buy a Castle ticket. For details, including to see the catalogue, visit www.andersonandgarland.com