National Gallery exhibit underscores Stieglitz's impact on art world.(Knight Ridder/Tribune News Service)

WASHINGTON _ When it came to America's artistic development, few had as important an impact as photographer and modern art proponent Alfred Stieglitz.

Stieglitz played a seminal role in fostering a modernist identity in art in the United States. Through three galleries he operated in New York City between 1905 and 1946, he helped unleash creative energies that would drive American art for much of the 20th century.

A new show at the National Gallery Art spotlights Stieglitz as a modern art visionary, connoisseur and artist.

"Modern Art and America: Alfred Stieglitz and His New York Galleries" presents nearly 200 paintings, sculptures, works on paper and photographs that Stieglitz featured in his various galleries over five decades.

A committed idealist who marched to his own beat, Stieglitz built a bridge between European art styles and American culture in the early 20th century. Later, he became a steadfast advocate for a group of American artists who possessed singular outlooks.

Stieglitz was born in Hoboken, N.J., in 1864, the son of a German immigrant. A pioneer in American photography, Stieglitz spearheaded the Photo-Secession movement at the turn of the century, which promoted the medium as an independent art form. He opened his first gallery at 291 Fifth Ave. in New York in 1905. Christened the Little Galleries of the Photo-Secession, the new gallery simply was known as 291.

The exhibit begins with a rich selection of works on paper Stieglitz displayed at 291 in 1908. A series of watercolors by French artist Paul Cezanne exhibit an unconventional use of compositional space. Nude figure drawings by French sculptor Auguste Rodin and French artist Henri Matisse display a raw sexual power that turned some viewers off. A classic portrait of Rodin facing his famous sculpture "The Thinker" by photographer Edward Steichen complements the assemblage.