In November 1917, as the killing fields of World War I swallowed the lives of millions of men, the 5th Marquess of Lansdowne, of Bowood House wrote a letter published in the Daily Telegraph newspaper in which he called for a negotiated peace with Germany.

Henry Petty-Fitzmaurice was not calling for surrender, but for negotiations and compromise. Unfortunately his idea was misinterpreted, and he was vilified and criticised by politicians and the media. His family even received hate mail.

Now, as part of the centenary commemoration of the end of the Great War, Bowood House, near Chippenham, is hosting an exhibition all about what came to be called the Lansdowne Peace Letter, examining the ideas behind the letter, the aftermath of its publication and the role of the family and the house itself during World War I.

Called A Patriotic Peace: The 5th Marquis and World War I, the exhibition of documents, letters, pictures, paintings and panels is the work of Bowood curator Dr Cathryn Spence.

“He was not saying we should surrender, but more and more people were dying, and little land was being won,” Dr Spence said. “But a number of people used this letter and misrepresented it.”

His letter said: “We are not going to lose this war, but its prolongation will spell ruin for the civilised world, and an infinite addition to the load of human suffering which already weighs upon it...We do not desire the annihilation of Germany as a great power ... We do not seek to impose upon her people any form of government other than that of their own choice.”

Lord Lansdowne was an experienced politician: he had been Governor General of Canada for five years, then Viceroy of India. He was Secretary of State for War between 1895 and 1900 and then for Foreign Affairs. During World War I he served in the coalition cabinet, and after much thought and discussion with his colleagues, he wrote his famous letter.

“He had always been part of the establishment,” Dr Spence explained. “His two sons were career soldiers. His second son, Charlie, was killed in October 1914.

“A hospital was set up at Bowood – so the war was very much in their focus and concern. He knew he had to say something.”

But Lord Lansdowne was isolated by his colleagues as a result and a piece of anonymous hate mail (included in the exhibition) described him as either “a paid agent of Germany or a decrepit old fossil in the last throes of senility.”

The aftermath of the letter proved disastrous not just for Lord Lansdowne, but for his family too.

“His eldest son, Lord Kerry, lost his seat as a Member of Parliament as a consequence, and did not support what he father had done,” she said. “But later, with hindsight, he realised how right his father had been.”

The defeat and humiliation of Germany, and the punitive reparations demanded, laid the foundations for World War II. Lord Kerry, who became the 6th Marquess of Lansdowne after his father’s death, had two sons die during the war, Edward who died in Normandy in 1944 and Charles, who was killed in action in Italy the same year.

Dr Spence, who also curates at the American Museum in Britain, near Bath, began planning and researching the exhibition in November.

It includes painted portraits and a host of photographs, showing the Lansdowne family but also the way Bowood was used as a hospital during the war.

Three panels recount the story of letter, beginning with the Patriotic Peace, then The Peace Letter and finally, Repercussions.

The exhibition will run in Bowood House throughout the 2018 season, and it is only one of a host of attractions at the house and gardens. As well as the house and landscaped grounds designed by Capability Brown, complete with lake and temple, Bowood has an adventure playground for the under 12s, complete with full size pirate ship.

Private tours of the four-acre Walled Garden will be offered on various dates, and the Woodland Gardens are open for six weeks from April 28 to early June, when the bluebells, azaleas, magnolias and rhododendrons are blooming.

Youngsters may also enjoy Tractor Ted’s Little Farm, where they can meet farm animals such as lambs, piglets, chicks and guinea pigs.

Bowood also has a programme of events over the season, ranging from the Classic Car and Motorcycle Show on May 6, to the Handmade Fair, starring Kirstie Allsopp, June 22-24.

Adult day tickets for Bowood House and Garden are £12.75, senior citizens £10.70, children aged five to 12 £9.70, and family tickets £38.25. For more information, visit bowood.org.