This fascinating morsel of information, gleaned from declassified KGB files, is not a minor detail in a country where anti-Semitism was a recognized state doctrine for decades. Starting in the 1930s, the Soviet regime - spurred on by its leader Joseph Stalin - launched a violent discriminatory campaign against Jewish citizens. (See the top 25 political icons: Lenin)
Born in 1870, Lenin identified himself simply as Russian. His official biography mentions only his Russian, German and Swedish origins. But one of the exhibition's priceless pieces adds a key new element to the official narrative.
In a letter to Stalin in 1932 - six years after Lenin's death - Anna Ulyanova, Lenin's older sister, wrote that their maternal grandfather "came from a poor Jewish family and was, according to his baptismal certificate, the son of Moses Blank." Blank was born in Zhitomir, Ukraine. In her letter, Ulyanova said her brother "had always thought highly of Jews." She also urged Stalin to reveal Lenin's Jewish background, concluding that "it would be wrong to hide it from the masses."
Stalin, however, ordered Ulyanova to keep Lenin's Jewish roots under wraps. A few years later, Stalin began to purge Jews from among the leaders of the revolution. Prior to his death in 1953, furthermore, he was preparing to send the whole Jewish population living in the Soviet Union to concentration camps in Siberia.
Most provincial Russian towns have a main road named Lenin Street. You can usually find shops selling luxury goods and banking centers there. They tend to contain all the flashiest symbols of the country's now capitalist society. (See TIME's photo-essay "The Bolshevik October Revolution.")
In the middle of virtually every central square, including in Belarus and in Ukraine, there is a high-rise statue of Lenin looking down on the rowdy shopkeepers. The Lenin paradox even goes further. Lenin is revered by Russia's radical fringe - people who feel nostalgic for the Soviet regime in general and for anti-Semitic Stalinism in particular.
The cult of Lenin has its physical focal point in Moscow's Red Square, where Lenin's mummified body is on permanent display in a mausoleum. In the past, Soviet citizens were expected to carry out pilgrimages to the Communist leader's resting place. (See photos of Aleksander Solzhenitsyn 1918 [EM] 2008)
Lenin's legacy is the subject of debate. Some Russian Communists want Lenin's cult to endure forever. But there are Russian Orthodox Christians who loathe Lenin because he destroyed Tsarism and because he turned atheism into a cornerstone of the official ideology. The latter, like many ordinary Russian people, want the man to be buried - with or without the honors reserved for a statesman.
Russians who began their working lives after the fall of the communist system often see things in the same ambivalent way. "Soviet children almost regarded Grandfather Lenin as Santa Claus," says Daria Beliaeva, a 30-year-old financial analyst who looks back at the Soviet era with nostalgia. "But later, I heard that the Germans sent him to Russia in an armored train to trigger the Russian revolution. I also heard that he ordered the destruction of about 100 churches," the practicing Orthodox adds disapprovingly.
Daria wasn't particularly moved one way or the other when she heard the Soviet idol had Jewish roots. "He had elements of good and evil in him. He put his mark on Russian history. Now, he needs to be buried."
Political expert Boris Kagarlitski, a former dissident and proud Leninist, says "the Russian authorities are using the debate about Lenin's Jewish background and about his burial as a pretext for taking people's minds off the real problems and issues facing our society."
Even if latent anti-Semitism does not play an active role in contemporary Russian politics, the Lenin exhibition could end up cutting into the famed revolutionary's enduring popularity. It might also persuade authorities to once and for all put his embalmed body to rest.