Alfred Stieglitz HonFRPS was an American photographer and modern art promoter who was instrumental over his 50-year career in making photography an accepted art form. In addition to his photography, Stieglitz was known for the New York art galleries that he ran in the early part of the 20th century, where he introduced many avant-garde European artists to the U.S. He was married to painter Georgia O'Keeffe.