How do you measure the United States in the 20th century without Langston Hughes, Zora Neale Hurston, Louis Armstrong and Duke Ellington?

You wouldn’t dream of it. The writers, poets, singers and musicians of the movement known as the Harlem Renaissance, centering around the New York neighborhood from 1919 to the end of the 1930s, loom large in the American cultural imagination. The period was when “Harlem became the symbol for the international black city,” as the novelist Ishmael Reed described it.

But what about the painters Laura Wheeler Waring, Charles Henry Alston and Malvin Gray Johnson? Or the sculptor Richmond Barthé? Hardly household names. And while other visual artists — Aaron Douglas, Jacob Lawrence, Archibald Motley Jr., Augusta Savage — have long been celebrated, their contributions have until recently been too often treated as a byway, separate from the rest of European and American modernism.

An ambitious new exhibition, “The Harlem Renaissance and Transatlantic Modernism,” opening Feb. 25 at the Metropolitan Museum of Art, hopes to shift our view of the time when Harlem, energized by the arrival of thousands of African Americans through the Great Migration, flourished as a creative capital.