Yale University is suing to keep one of Vincent Van Gogh’s most famous works.

The Ivy League university sued on Tuesday in federal court in Connecticut to assert its ownership rights over The Night Cafe. It also seeks to block a descendant of the original owner from claiming it.

Pierre Konowaloff is the purported great-grandson of industrialist and aristocrat Ivan Morozov, who owned the painting in 1918.

Russia nationalized Morozov’s property during the communist revolution. The painting, which the Soviet government later sold, has been hanging in the Yale University Art Gallery for almost 50 years.

The school says it wants to remove any cloud over ownership of the painting, which shows the inside of a nearly empty cafe, with a few customers seated at tables along the walls.

The school says it wants to remove any cloud over its ownership.

Yale’s lawsuit says that Konowaloff’s attorney last year asserted that his client owned the 1888 painting and sent a draft complaint of a federal lawsuit. Konowaloff also has publicly said he wants title of the painting transferred to the Russian state and wants to receive personal financial compensation, according to the lawsuit.

It was unclear who represented Konowaloff, who lives in France.

Konowaloff claims the Soviet nationalization of property was illegal, so that title never passed from his great-grandfather, according to Yale’s lawsuit.

Paintings that were nationalized by the Soviet government figure prominently in the collections of premier institutions throughout the world, according to the lawsuit. The Russian nationalization of property, while sharply at odds with American values, did not violate international laws, the lawsuit says.

“The implication of his argument is that American courts should try to undo the entire program of property reform undertaken by the Russian government in the early part of the 20th century, invalidating the transfers of title of Russian citizens’ property that Russia effectuated within its own borders,” Yale said. “It was accepted at the time, as it is now, that the sales by the Soviet government were valid, as were later acquisitions of the paintings.”

Yale received the painting in 1961 through a bequest from Stephen Carlton Clark, a Yale alumnus who founded the Baseball Hall of Fame.

Clark bought the painting from a gallery in New York City in 1933 or 1934 and had it exhibited at the Museum of Modern Art, the lawsuit said.

“Yale had no reason to question the legitimacy of Mr Clark’s generous bequest in 1961. Nor does it today,” Yale’s attorney wrote.

“In the more than 90 years since the painting was nationalized, the more than 70 years since the Soviet government sold the painting and the almost 50 years since Clark bequeathed it to Yale, witnesses have died and documentary evidence has been lost,” the lawsuit said.