For the first time, the dress Marian Anderson wore to sing at the Lincoln Memorial 75 years ago after being denied access to a Washington concert hall because she was black, is going on display at the Smithsonian.

On Easter Sunday 1939, the classical singer accepted Eleanor Roosevelt’s invitation to give a public concert and wrapped herself in a fur coat that cold day after she was kept out of Washington’s D.A.R Constitution Hall. Beneath the coat, she wore a striking orange-and-black ensemble and carried herself with pride, historians said.

The outfit she wore to make history was uncovered among the late singer’s belongings and put on display Tuesday at the Smithsonian’s National Museum of American History through September. Wednesday marks the 75th anniversary of Anderson’s Easter Sunday performance at the Lincoln Memorial.

Curators learned earlier this year that the dress had been kept hidden away all these years.

“I definitely would have loved to have had something iconic” to represent Anderson, said Dwandalyn Reece, who is building a collection for the National Museum of African American History and Culture. “But I just didn’t expect for this to exist.”

The two-piece concert attire is part of a collection recently donated to the museum by Ginette DePreist of Scottsdale, Ariz. DePreist is the widow of Anderson’s nephew, the late music conductor James DePreist.

Ginette DePreist said the dress had been long forgotten. It was among the belongings she salvaged from Anderson’s damp basement at the Connecticut home where the singer lived for 40 years before moving to Oregon to live with the DePreists. Anderson died in April 1993.