Question: What year was the painting put into a hidden room?
About the article "Portrait of Dr. Gachet", section "Original version".

Candidate passages:
Original version.
First sold in 1897 by Van Gogh's sister-in-law for 300 francs, the painting was subsequently bought by Paul Cassirer (1904), Kessler (1904), and Druet (1910).
In 1911, the painting was acquired by the Städel (Städtische Galerie) in Frankfurt, Germany and hung there until 1933, when the painting was put in a hidden room.
The Reich Ministry of Public Enlightenment and Propaganda confiscated the work in 1937 as part of its campaign to rid Germany of so-called degenerate art, leading to Hermann Göring hurriedly selling it to a dealer in Amsterdam.
The dealer in turn sold it to collector Siegfried Kramarsky, who brought it with him when he fled to New York, where the work was often lent to the Metropolitan Museum of Art.
Kramarsky's family put the painting up for auction at Christie's New York on May 15, 1990, where it became famous for Ryoei Saito, honorary chairman of Daishowa Paper Manufacturing Co., paying US$82.5 million for it, making it then the world's most expensive painting.
Remarkably, two days later Saito would buy Renoir's Bal du moulin de la Galette for a nearly-as-much $78.1 million at Sotheby's.
The 75-year old Japanese businessman briefly caused a scandal when he said he would have the Van Gogh painting cremated with him after his death, though his aides later claimed Saito threatening to torch the masterpiece was just an expression of intense affection for it.
Though he later said he would consider giving the painting to the Japanese government or a museum, no information has been made public about the exact location and ownership of the portrait since his death in 1996.
Reports in 2007 have claimed the painting was sold a decade earlier to the Austrian-born investment fund manager Wolfgang Flöttl.
Flöttl, in turn, had reportedly been forced by financial reversals to sell the painting to parties as yet unknown.
The "Portrait of the Duchess of Alba" was painted in 1797 by Spanish painter Francisco José de Goya y Lucientes.
The work is kept at the New York Hispanic Society, owned and operated by the Hispanic Society of America.
In the painting, the duchess (María Cayetana de Silva, 13th Duchess of Alba) is thirty-five years old, and her husband had died the year before, so she is dressed in mourning clothes (attire).
In the painting, she is pointing to the ground, where the words "solo Goya" are lightly engraved.
She is wearing two rings, one engraved with the word "Alba", the other engraved with "Goya".
The inscription of the word "solo" was initially hidden, but after the painting was restored the word was revealed.
This work is among a number Goya painted of the duchess.
When she retreated to a residence after her husband died a year earlier for a period of mourning, Goya followed and created numerous paintings and sketches of the duchess during her stay.
One day, the duchess walked into Goya's studio and requested that he put on the duchess' makeup, then create a painting for her, which he did.
This painting is the "Portrait of the Duchess of Alba", painted at her request. 
The story revolves around a Bostonian painter named Richard Upton Pickman who creates horrifying images.
His works are brilliantly executed, but so graphic that they result in his membership in the Boston Art Club being revoked and himself shunned by his fellow artists.
The narrator is a friend of Pickman, who, after the artist's mysterious disappearance, relates to another acquaintance how he was taken on a tour of Pickman's personal gallery, hidden away in a run-down backwater slum of the city.
As the two delved deeper into Pickman's mind and art, the rooms seemed to grow ever more evil and the paintings ever more horrific, ending with a final enormous painting of an unworldly, red-eyed and vaguely canine humanoid balefully chewing on a human victim.
A noise sent Pickman running outside the room with a gun while the narrator reached out to unfold what looked like a small piece of rolled paper attached to the monstrous painting.
The narrator heard some shots and Pickman walked back in with the smoking gun, telling a story of shooting some rats, and the two men departed.
Afterwards the narrator realized that he had nervously grabbed and put the rolled paper in his pocket when the shots were fired.
He unrolled the paper to reveal that it is a photograph not of the background of the painting, but of the subject.
Pickman drew his inspirations not from a diseased imagination, but from monsters that were very much real. 
Local legend asserts the existence of a secret hidden room at Stafford Hall and that anyone discovers the room dies shortly afterwards.
Legend also holds that a prominent magistrate from Hagerstown found the room in 1924 and died within the year.
In 1926, Leo Cohill's nine-year-old daughter Margaret became ill after finding the room and admitted what she had done on her deathbed, begging her family members to not seek out the room. 
The painting was exhibited on numerous occasions during Xu's life.
However, it disappeared from public view in 1954, a year after Xu's death.
According to Sotheby's Asia chairman Patti Wong, Xu gave the painting to a close friend named Huang Menggui.
After Huang died, his descendants approached the National Museum of Singapore in the hope that the museum could take the painting into its collection, but it did not happen for unspecified reasons.
Huang's descendants then approached Singaporean collector Tan Tsze Chor, but Tan died abruptly, before the deal was made.
The painting eventually landed in the hands of an anonymous Asian collector, until being put up for auction in 2007.