On March 17, 1941, President Franklin D. Roosevelt accepted the completed National Gallery of Art in Washington, D.C., on behalf of the American people. The museum arose from Andrew W. Mellon's gift of collection and construction funds, accepted by Congress in 1937, and its John Russell Pope-designed West Building was then among the largest marble structures in the world. The opening created a national art museum independent in identity from the Smithsonian's earlier gallery and immediately framed private collecting as a public cultural resource. Its founding collection, later expanded by Kress, Widener, Rosenwald, Dale, Mellon family, and other donors, gave the United States a canonical old-master and American collection on the National Mall.
The opening established one of the United States' central public art institutions and encouraged major private collectors to give collections for national access.