NEW YORK — Two New York museums asked a judge recently to declare that they are the legitimate owners of two Picasso paintings whose ownership has been challenged by a man who says they were sold under duress in Nazi Germany.

The 1935 sale of Boy Leading a Horse and Le Moulin de la Galette was legitimate, the Museum of Modern Art and the Solomon R. Guggenheim Foundation said in a suit filed in Manhattan federal court.

The two museums are suing Julius Schoeps, a scholar at the University of Potsdam, who says he is the heir of wealthy German Jewish art collector and banker Paul Robert Ernst von Mendelssohn-Bartholdy and that the banker was forced to sell the paintings in Nazi Germany before his death in 1935.

William Paley, a long-time trustee of MoMA who would eventually be its president and chairman, bought Boy Leading a Horse in 1936 and gave it to the museum in 1964. It is one of the best-known paintings in the museum’s collection.

Le Moulin de la Galette was transferred to the Guggenheim in 1963 by Justin Thannhauser, a leading German Jewish art dealer and von Mendelssohn-Bartholdy business associate, and absolutely acquired by the museum in 1978 after his death, the museum said.

The museums said Schoeps has no claim to the paintings because they were left to von Mendelssohn-Bartholdy’s second wife, Elsa Lucy Emmy Lolo von Lavergue-Peguilhen, who was not Jewish, prior to their sale. They said Berlin-based Von Mendelssohn-Bartholdy’s prominence in society helped shield him from Nazi persecution.

"There is no evidence that von Mendelssohn-Bartholdy or his second wife suffered pressure to sell their art through any discriminatory measure," court papers said.

But Schoeps, European-Jewish studies director at the University of Potsdam in Germany, has said his great uncle’s paintings were sold under pressure following Adolf Hitler’s rise to power in 1933.

Schoeps’ lawyer John Byrne did not immediately comment.

Last year, Schoeps lost a claim contesting the ownership of Portrait of Angel Fernandez de Soto, a $60 million Picasso painting that belonged to the British composer Andrew Lloyd Webber’s Art Foundation.

It was due to be auctioned, but the Lloyd Webber foundation withdrew the 1903 painting, also known as The Absinthe Drinker, saying a "cloud of doubt has been recklessly placed" on its ownership. – Reuters