A rare window into life in imperial Russia is due to open on Monday, when hundreds of letters, postcards, photographs and even menus from the court of Tsar Alexander III are put up for auction in Geneva.
The documents were all sent by Alexander's children, Nicholas (who later became Nicholas II), George, Michael, Olga and Xenia to their Swiss tutor Ferdinand Thormeyer.
Mr Thormeyer was born and brought up in Geneva, but emigrated to Russia as a young man where - in 1886 - he became a tutor of French language and literature to the imperial children.
Throughout his time with them the children wrote him letters, partly as a way of practising their French.
But when Mr Thormeyer left Russia in 1899, they continued to write to him and to his family; Olga's letters only stopped when she died in exile in 1960.
The documents were only discovered this year, when a descendant of Mr Thormeyer's was clearing out his attic. There, hidden in an old trunk, he found letters spanning 70 years.
"He came to see us first with just 20 letters," recalls Christina Robinson of the Geneva auction house Hotel des Ventes. "He wondered if they were worth anything."
"We saw that the letters had been written by Olga Kulikovsky, Grand-Duchess Olga Alexandrovna in fact, the youngest sister of Tsar Nicholas II."
A visit to the attic revealed more than 1,000 more documents, including family photographs, postcards, and even sketches.
What the documents reveal are an intimate portrait of life at the court of the tsar and the enormous affection the children had for their Swiss tutor.
"I think when Alexander III died in 1894 Mr Thormeyer became, probably unwittingly, almost a father figure for them," says Mrs Robinson.
"They address their letters to him 'my dear Siocha', which was their nickname for him, and Mikhail signs himself 'your loving Misha', rather familiar for a grand-duke."
The children also clearly felt they could confide their feelings to their tutor in a way that they perhaps couldn't to their families.
Grand-Duke George, for example, suffered from tuberculosis, and - sent away in 1896 to take the cure - wrote to Mr Thormeyer complaining about his doctor: "I do fear sometimes he's injecting me with something other than the medicine I actually need…the man is a dog."
Mikhail, meanwhile, was having difficulty accepting his role as heir to the throne once his brother Nicholas became tsar.
In 1904, when Nicholas's son Tsarevich Alexis was born, Mikhail wrote to Mr Thormeyer: "I thank God for liberating me from the burden I have been carrying all these years."
And in 1910, Grand-Duchess Olga explains bluntly why Mikhail, at the time causing scandal because of his private life, would be unable to attend the coronation of his cousin George V of England.
"Mikhail is sick, he has come out in a most horrible and disgusting rash, with pink spots all over his face," she wrote. "Naturally, with his head all bandaged to cover them up, he cannot possibly represent Russia at the coronation."
What comes across most of all, however, is the complete separation of the tsarist family from life in everyday Russia at the time.
While discontent among ordinary people mounted, the imperial children were busy visiting and receiving visits from Europe's royal families, almost all of whom were their cousins.
Their letters tell stories of picnics, bicycle rides, and bear hunts.
"On an almost daily basis Mikhail goes shooting," says Mrs Robinson, "and he often writes to Ferdinand Thormeyer to tell him how many bears he managed to shoot on that particular outing."
"They are so far detached from reality that they don't even know it," she adds.
A glance at various court menus saved by Ferdinand Thormeyer proves the point.
In the cold November 1910 in St Petersburg, when many Russians were going hungry, the royal family were having pheasant, artichoke, and asparagus for lunch, followed by fresh fruit and ice cream, sweet pastries, tea, coffee and liqueurs.
Life in exile
Of course, it all came to a bloody end after the revolution of 1917. Mikhail, Nicholas II and his entire family were shot, Olga and Xenia escaped into exile.
But there is little in the Geneva letters to indicate that any of them really saw what was coming.
"We actually have one letter from Olga in 1914, which starts off talking about the weather and her flower collection,' says Mrs Robinson.
"There's really no indication that she was aware of what was happening around her, and the political situation in Russia.
"After that we jump to 1920, so there is a kind of blackout through most of the trouble."
But, safely exiled in Denmark and then Canada, Olga continued writing to her beloved tutor.
"She talks a lot about her love for Russia, and how much she misses it," explains Mrs Robinson.
"She says she always feels Russian, and she writes of her childhood, her happy memories… she still wants, even at the end of her life, to maintain a contact with her past life."
Now, that long-forgotten life will become more public; the letters and other documents are expected to sell for $70,000-$100,000 (£44,544-£63,634).
The auction house has divided them into different lots, but the hope is that they will all be bought by a library or foundation, in order to make this previously unknown historical archive accessible to all who are interested.