IT is a spectacular treasure trove meticulously collected by the generations of a Scottish family steeped in the nation's history.

But now the collection of Fettercairn House is to go under the hammer in London next week with more than 400 works of art being sold to the highest bidder.

The incredible hoard, amassed by the Forbes family, boasts rare paintings, furniture, books, jewellery and personal possessions.

Among the items up for sale are a broadsword wielded by the Jacobite Alexander Forbes in the risings of 1715 and 1745, artworks by John Robert Cozens, Sir Henry Raeburn and Allan Ramsay, and a jewel said to bear a remarkable resemblance to the famous Darnley Jewel, normally on display in Holyrood Palace in Edinburgh.

The previously unknown “Fettercairn Jewel,” which was discovered in a closet off the library, is set to fetch up to £50,000.

At least £1.2 million is expected to be generated by the sale, which spans the 16th century to the present day, and is expected to attract the interest of museums and galleries.

David Macdonald, Sotheby’s specialist in charge of the Fettercairn House sale, said: “In some respects, this is the story of Scotland over the last 250 years.

"From Jacobite swords and sporrans, and late 18th-century decorative pieces, to Grand Tour souvenirs – all these treasures found their way to Fettercairn House."

One of Edinburgh's leading families in the 18th century, the Forbes clan owed its prosperity to Sir William Forbes, one of Scotland’s leading authorities on finance and a trusted adviser to William Pitt the Younger.

Fettercairn came into the family's orbit when his son, also William, fell in love with Williamina Belsches, the sole heir to the property, and married her in 1797.

Mr MacDonald said: "The lives and loves of the Forbes family, their academic interests and passions were reflected in the objects they acquired and treasured. Now these carefully displayed, stored or locked away heirlooms come to light to be shared and discovered.”

The sale, on Tuesday, will also see around 70 items from the collection the Marquis of Lothian - a title currently held by the MP Michael Ancram - drawn from the attics and stores of Monteviot House.

Harry Dalmeny, Sotheby’s UK Chairman, said: “These two collections, rich in content, say as much about the history of Scotland as they do about the families who assembled them over nearly four centuries.

"The Forbes family of Aberdeenshire, a clan replete with bankers, statesmen and Jacobite rebels stand here united with the lowland Kerrs, Stuart courtiers, soldiers, politicians and collectors.

"The items present an encyclopaedic array, and whilst each lot tells its own tale, together they paint the most vivid picture, and celebrate the unique families and country from which they have come.”