Lonnie Bunch is retiring from his role as secretary of the Smithsonian Institution, the organization announced in a statement on Tuesday, amid the Trump administration’s increased attacks on the nation’s preeminent museum network.

Bunch, who was the first Black person and first historian to lead the Smithsonian, served in the role for seven years.

The departure comes as the Trump administration has placed increased scrutiny on the Smithsonian museums, alleging the museums need to do more to “reflect the unity, progress and enduring values that define the American story.”

“It is with very mixed emotions and heartfelt gratitude that I announce my retirement from the Smithsonian,” Bunch said in a statement released by the institution.

He added, “I have spent nearly half of my life working at and being part of the Smithsonian family, and what a privilege it has been.”

On July 4, the nation’s 250th birthday, the White House released a 162-page report titled “Saving America’s Story” that accused museum leadership of “extreme political activism” and history erasure. Later in the month, President Donald Trump signed an executive order requiring signs to be installed outside the Smithsonian’s National Museum of American History to warn visitors about “inaccurate information” presented in the museum.

“It is time for my next chapter, a chapter that will allow me to continue to protect the integrity of the Smithsonian and to champion the importance of history that illuminates and celebrates the complex story of our nation,” Bunch said.

Bunch began his career at the Smithsonian in 1978, when he served in curatorial and leadership positions at the National Air and Space Museum and the National Museum of American History. He briefly left the Smithsonian to serve as president of the Chicago Historical Society but returned in 2005 to establish the National Museum of African American History and Culture.

“From his days as a young curator at the National Air and Space and American History Museums through his tenure as the founding director of the African American History and Culture Museum and culminating in his distinguished service for the past seven years in the Smithsonian’s top job, Secretary Bunch has pursued excellence in the telling of our nation’s story,” said Chief Justice John Roberts, who serves as chancellor of the Smithsonian, in a statement.

Details about Bunch’s replacement will be available at a later date, the Smithsonian said in its release.

Trump has sought to remake the nation’s cultural institutions in his image. Shortly after he returned to Washington, he removed most of the board of the Kennedy Center — Washington’s major theater and arts center — and assumed the chairmanship of the board.

The new board, loaded with his allies, has repeatedly tried to attach Trump’s name to the Kennedy Center.

Unlike the Kennedy Center, Trump does not have the power to select or remove the Smithsonian leadership at will. But he can have tremendous influence in the process to pick its next leader through the selection of board members.