Financier Andrew Mellon served as Secretary of the Treasury under President Harding. His was a family banking fortune that Mellon used to advance his interests in coal, aluminum and oil. Although opinion is divided about Mellon's motives, it is clear that his priority was tax reduction for the wealthy. He was also instrumental in blocking American participation in the League of Nations after World War I. His many charitable donations towards the end of his life secured him a posthumous reputation as a philanthropist. Mellon's personal art collection became the basis of the National Gallery of Art.