Within the overall process of “internationalization” of science and mathematics in the first part of the 20th century, the collaboration between foundations and mathematics had particular features. The talk will discuss them in detail at the example of support by the American Rockefeller Philanthropy in the 1920s and 1930s. Pure science, symbolized by mathematics, brought much needed social legitimacy to the Rockefeller empire via philanthropic foundations. Mathematics, in turn, received much needed money for its autonomous development which it could raise neither from the state nor from industrial enterprises, both being either bankrupt (at least the states in Europe) or more interested in immediate “applications,” including elementary education.