LONDON.- The British Museum on Thursday named Nicholas Cullinan, an art historian who currently runs the National Portrait Gallery in London, as its new director, ending an unsettled period in which the august institution lacked a permanent leader.

Cullinan, 46, will step into the role in the summer, the British Museum said in a news release. He will immediately face a host of challenges, including the fallout from an embarrassing scandal in which the museum says a former curator stole over 1,800 items from its storerooms, then sold many of the artifacts on eBay.

Cullinan will also need to lead an extensive fundraising drive to pay for a major refurbishment to the museum. And he will have to deal with demands for the return of contested artifacts to their countries of origin, including the Parthenon Sculptures, also known as the Elgin Marbles, and a collection of Benin Bronzes.

In the news release, Cullinan said he was looking forward to taking the museum “into a new chapter.” Under his leadership, he expected the museum to undergo “significant transformations, both architectural and intellectual,” he added. “I can’t imagine a better challenge or opportunity to build on that than collectively reimagining the British Museum for the widest possible audience,” he said.

The British Museum has been without a permanent director for seven months, since Hartwig Fischer, a German art historian, resigned last August. Fischer’s departure came shortly after The New York Times and the BBC reported that he had downplayed concerns that a curator was stealing items from the museum. In September, the museum appointed Mark Jones, a former leader of the Victoria and Albert Museum, as Fisher’s interim replacement.

Cullinan — who is seen by museum world insiders as an energetic leader, capable of overhauling tired institutions — had been the favorite for the British Museum job. Last year, he reopened the National Portrait Gallery after a highly praised $53 million renovation.

Cullinan, who was born in Connecticut but grew up in Britain, studied art history at the prestigious Courtauld Institute of Art in London. He then worked as a curator of international modern art at Tate Modern, before spending two years as the curator of modern and contemporary art at the Metropolitan Museum of Art in New York.

This article originally appeared in The New York Times.