On March 24, 1937, Andrew W. Mellon's birthday, an Act of Congress accepted Mellon's proposed gift of an old-master collection and construction funds, authorizing a new National Gallery of Art on the National Mall in Washington, D.C. The act transformed a private collecting project into a national museum built around free public access, public-private governance, and a collection meant to rival European national galleries. The new institution also inherited the name previously used by the Smithsonian's art gallery, which was later renamed the National Collection of Fine Arts and is now the Smithsonian American Art Museum. Although the West Building did not open until 1941, the March 24 congressional act was the legal and institutional foundation for one of the United States' central art museums.
The act created a durable model for a free national art museum supported by federal stewardship and private gifts.