In the gloom of his small mausoleum near the village of Doorn, 16 miles east of the Dutch city of Utrecht, lies the mummified corpse of Kaiser Wilhelm II. His lead coffin is draped with a flag bearing the black eagle of Prussia. Surrounding the mausoleum, at his request, is a rhododendron garden.

According to some historians, at the end of the first world war the last German emperor was only able to flee the British and French gallows to live in exile in the Netherlands because of the help of his distant cousin, the Dutch queen Wilhelmina.

She had used her blood ties to persuade Wilhelm not to invade the Netherlands during the war, in which the country remained neutral. Academic research is soon expected to definitively prove what much of the evidence suggests: that the Dutch queen later repaid Wilhelm by letting him cross the border to safety.

Now, in the centennial anniversary of the end of the war, the Dutch royal family is again emerging as the key to saving the kaiser, albeit now it is his former house, belongings, resting place and 45 hectares of grounds at risk of ruin.

Facebook Twitter Pinterest Huis Doorn. Photograph: Judith Jockel/The Guardian

The Kaiser bought Huis Doorn, his home until his death in June 1941 at the age of 82, from Baroness Ella van Heemstra, the mother of Audrey Hepburn. Between September 1919 and February 1922, five trains pulling 59 carriages arrived at Zeist station filled with his possessions.

Today those possessions remain largely untouched. On his deathbed lies a small bunch of snowdrops and a note from his mourning son, Adalbert, who was serving in Hitler’s Wehrmacht when his father died. Wilhelm’s morning gown hangs in his bedroom, above his fur-trimmed slippers. A framed postcard from his grandmother, Queen Victoria, takes pride of place. His cigars sit by an ashtray.

Facebook Twitter Pinterest A framed card from Queen Victoria was placed nearby. Photograph: Judith Jockel/The Guardian

The house was taken as war booty by the Dutch state in 1946, and opened to the public as a museum in the 1970s. But the sensitive nature of the estate and controversial legacy of Wilhelm resulted in decades-long underinvestment, and difficulties in attracting visitors. In 2013, the Dutch government stopped its annual €250,000 contribution towards the museum’s running costs.

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That decision was reversed a year later, but funding was guaranteed for only four years. That was when the Dutch royal family stepped in again. Princess Beatrix, the Dutch queen until her abdication in 2013, visited the museum in 2014 to open an exhibition on the Dutch experience of the first world war.

Facebook Twitter Pinterest Wilhelm’s library at Huis Doorn. Photograph: Judith Jockel/The Guardian

“It had been a continuous discussion from the 80s and 90s: should the Netherlands support a German museum, as some called it?” said Herman Sietsma, the director of the foundation that runs the museum. Beatrix’s visit “was very important”, he added. “We relied on the idea that this should build support for the museum.”

Beatrix returned again this month, to open an exhibition in Kaiser Wilhelm’s house of the works of the German sculptor, Käthe Kollwitz, to whom Wilhelm – before the war – had refused to give an honour, on the grounds that she was a woman.

“We would not be able to properly tell that story without this exhibition,” Sietsma said. “It was very supportive when Princess Beatrix came in 2014 and it is very supportive that she has come again now.”

Facebook Twitter Pinterest The dining room at Huis Doorn. Photograph: Judith Jockel/The Guardian

The challenge now, Sietsma said, was to attract more people to the museum, and to explain that it was not a German museum, but one chronicling European history.

Every year on Wilhelm’s birthday, a group of up to 40 German monarchists pay their respect at the mausoleum. “I think it is very important to say: we don’t honour Kaiser Wilhelm here,” Sietsma said. “And we instruct all our guides to say ‘we don’t honour him and nobody wants to honour him. But we remember’.”