Alfred Stieglitz opened the New York gallery known as 291 in 1905 and named it after its address.
The gallery began as the Little Galleries of the Photo-Secession at 291 Fifth Avenue in Manhattan. Its short name, 291, became the identity most closely associated with the space. Stieglitz used it to exhibit photography and modern art to American audiences.
The gallery presented work by photographers such as Edward Steichen and also introduced American viewers to European modernists, including Pablo Picasso, Henri Matisse, and Constantin Brâncuși. O'Keeffe's work was shown there after Stieglitz became familiar with her drawings.
A common mix-up is treating 291 as an artist's name or a painting title. It was a gallery, and its name came directly from the building's street number on Fifth Avenue.