John D. Rockefeller (1839-1937) started his career selling potatoes and candy as a teenager before becoming a bookkeeper earning $15 per month. He went on to found Standard Oil Company and became the wealthiest person of his time through strategies like buying out competitors and lowering kerosene prices using new transportation methods like pipelines and trains. In retirement after age 40, Rockefeller spent over 40 years philanthropy including massive donations to establish the University of Chicago and Rockefeller University.