IN 1859, WITH $1,000 in savings and a $1,000 loan from his father, Cleveland, Ohio, resident John D. Rockefeller formed a partnership with Maurice B. Clark and became a commission merchant, a go-between who received a percentage of commission on each sale. During the Civil War, Rockefeller prospered from the generous prices the U.S. government paid him, and he used the profits from that business as well as credit to finance his entry into the oil business. In 1863, Rockefeller and his partners founded Rockefeller, Andrew & Flagler. When the partnership split, Rockefeller and Andrews bought out the other partners (by then, three) for $72,500.

By 1868 this oil-refining business was the world's largest, and in 1870 Rockefeller created Standard Oil Company of Ohio, capitalized at ...