The bust of the Egyptian queen Nefertiti, which has been on display in Berlin for nearly four years, is now the subject of a major controversy over how Germany acquired the sculpture.

The bust of ancient Egyptian Queen Nefertiti has been one of Germany’s most treasured cultural possessions since German archaeologists discovered the exquisitely crafted 3,350-year-old artwork in the sands of Egypt almost a century ago.

Renowned for its timeless beauty, the sculpture attracts more than half a million visitors a year to the Berlin museum where it is on display, and it has long been a source of friction between Germany and Egypt, which has been demanding its return for decades.

Those calls are now likely to grow more forceful following the discovery of a document indicating that a top German archaeologist cheated to ensure Egyptian officials would let him have the bust.

The German Oriental Society (DOG), set up in 1898 to rival British and French archaeological finds in the Middle East, found Nefertiti in 1912 during excavations in Amarna, about 320km south of Cairo.

In Jan 1913, there was a meeting to divide up the spoils of that expedition between Germany and Egypt on a strict 50-50 basis.

The society has confirmed the existence of a written account of the negotiations on Jan 20 1913, between its leading archaeologist Ludwig Borchardt and Gustave Lefébvre, Egypt’s inspector of antiquities.

The record, written in 1924 by a DOG secretary who was present at the meeting, said Borchardt tried to make Nefertiti look unattractive because “he wanted to save the bust for us”. Borchardt, the secretary wrote, “didn’t show the most advantageous photograph” of Nefertiti.

The bust lay wrapped in a crate with an open lid and the lighting in the room was kept dim during the inspection, which took place at the headquarters of the DOG in Amarna, the secretary wrote. It is unclear whether Lefébvre took the trouble to lift the bust out of the crate to inspect it.

Borchardt also told Lefébvre that the bust was made of gypsum, which was untrue. It has a limestone core covered in modelled and painted gypsum. His claim amounted to “cheating” regarding the material, the DOG secretary wrote.

News magazine Der Spiegel reported this week that the document had only just surfaced in the DOG’s archives.

But Felix Blocher, the secretary of the DOG, said: “We still believe that everything is legitimate.”

Berlin will not return Nefertiti without a fight. She is to the German capital what the Mona Lisa is to Paris.

Ever since she first went on display in 1923, she has startled visitors with her beguiling features that show the concept of human beauty has not changed through the ages.

Hitler stopped plans to give back bust

She even enchanted Adolf Hitler, who put a stop to plans by his ministers, Hermann Göring and Joseph Goebbels, to hand the bust back in the 1930s to win favor with Egypt.

The German government declined to comment on the document but a spokeswoman for the Prussian Cultural Heritage Foundation, which is in charge of Berlin’s state-run museums, insisted the finds were divided up fairly in 1913.

“The foundation is not worried that it will have to give Nefertiti back because the division of the finds was legal,” a spokeswoman said.

Egypt’s demand for Nefertiti is part of a campaign to retrieve ancient Egyptian treasures taken by archaeological expeditions from European colonial powers in the 19th century and now on display in museums elsewhere.