John Davison Rockefeller Sr. was an American business magnate and philanthropist who is widely considered the wealthiest American of all time. He co-founded the Standard Oil Company, which dominated the oil industry and became the first great U.S. business trust. As kerosene and gasoline grew in importance, Rockefeller's wealth soared and he became the world's richest man and the first American worth more than a billion dollars. In his later life, he dedicated himself to philanthropy, establishing foundations that had a major effect on medicine, education, and scientific research.