John Rockefeller was already well known by the time he founded Standard Oil. But he wasn’t as rich. He dealt in grains and meats, but soon discovered the promising new commodity of oil. Rockefeller opened up a refinery near Cleveland, Ohio, quickly growing it to the largest one in the region, and decided to give up everything else to focus exclusively on oil.

On this day, January 10th, in 1870, Rockefeller and several partners incorporated his company Standard Oil. Of the 10,000 initial shares, Rockefeller took for himself slightly more than a quarter, the largest share of any partner. Over the ensuing several decades he outworked competitors to grow his company into one of the largest monopolies, and then shrewdly went around anti-trust legislation drafted in part to address the practices of Standard Oil.

The trustbusters eventually caught up to Standard Oil, and it was forced to break up into 34 smaller entities, many of which make up the bulk of the American oil industry today. The Chevron company of today used to be Standard Oil of California and Exxon was Standard Oil of New Jersey.