High Quality Content by WIKIPEDIA articles! A foundation in the United States is a type of charitable organization. However, the Internal Revenue Code distinguishes between private foundations and public charities. Private foundations have more restrictions and fewer tax benefits than public charities like community foundations. The two most famous philanthropists of the Gilded Age pioneered the sort of large-scale private philanthropy of which foundations are a modern pillar: John D. Rockefeller and Andrew Carnegie. The businessmen each accumulated private wealth at a scale previously unknown outside of royalty, and each in their later years decided to give much of it away. Carnegie gave away the bulk of his fortune in the form of one-time gifts to build libraries and museums. Rockefeller followed suit, but then gave nearly half of his fortune to create the Rockefeller Foundation.