In 1971, Tennyson Schad opened Light Gallery in New York City. It was one of two galleries devoted solely to photography open at the time. What distinguished Light Gallery was it's aim of representing exclusively contemporary photographers. In time, the gallery showed Harry Callahan, Aaron Siskind, Frederick Sommer, Paul Strand, Robert Mapplethorpe, Garry Winogrand and many more.
The other historically important thing about Light Gallery was that it produced quite a few current gallery directors including Laurence Miller, Peter MacGill, Robert Mann and Harold Jones.
Here are some samples of announcements for exhibitions held at the gallery:
here and here.