There was one more milestone to come. In 1955 Anderson broke the color barrier for soloists at the Metropolitan Opera, singing the small but crucial role of the fortune teller Ulrica in Verdi’s “Un Ballo in Maschera.” In earlier years, European houses had approached her about performing in opera, but she declined, having had no opportunity to learn the repertory or develop her acting skills.

But as the civil rights movement gained headway in America, Rudolf Bing, the Met’s general manager, realized that the company had to respond. He wanted an artist without controversy to be the first. And by then, who didn’t admire Marian Anderson?

She was very hesitant. But, after some encouraging work with opera coaches, she decided to proceed; received $1,000 per performance, the highest fee at the house at the time; and came to embrace her pioneering role.

When the production opened, the starry cast included Zinka Milanov, Richard Tucker, Leonard Warren and the young Roberta Peters, with Dimitri Mitropoulos conducting. Recalling the moment when the curtain went up, Anderson later wrote, “I trembled, and when the audience applauded and applauded before I could sing a note I felt myself tightening into a knot.”

She was almost 58, past her vocal prime. But she did it, won solid reviews and a place in history. Sony’s set includes an album of excerpts from the opera recorded in a studio around the same time (though Jan Peerce replaced Tucker). Compelling moments in Anderson’s singing of the role suggest what her career in opera might have been.

The American Experience documentary opens with poignant footage of Anderson on the morning of her Lincoln Memorial concert, going though sound checks on the platform, looking nervous and wary. For all her fears, the concert was a triumph. A mixed crowd of 75,000, more people than had ever gathered on the Mall, heard Anderson sing a 30-minute program that opened with “My Country ’Tis of Thee,” included Schubert’s “Ave Maria” and a Donizetti aria, and ended with a group of spirituals. Millions more heard it broadcast on the radio.

In time, the Daughters of the American Revolution dropped its exclusionary policy at Constitution Hall. Anderson performed there in a war relief benefit in 1943. And it was sweet justice when, in 1964, she began an extended farewell tour with a recital there, too.