John D. Rockefeller
Standard Oil Company
At age 20 he was thriving at his job so he decided to venture out and to a business that dealt with hay, meat, and grain. The company's gross was $450,000 the first year. Thinking that he was doing good he decided to go try for the Oil business in 1860 and had his first refinery in 1863 and co-founded the Standard Oil Company. In the early 1880's his company dominated the oil industry and had a net worth of $55 million.
End of Life
Towards the end of his life he had a problem with Henry Ford using alcohol to run his car instead of oil or gasoline. So he pushed to get the alcohol banned and it did so that he could get his oil used instead. At the age of 97 he died the richest man to ever live in the world with a net worth of 350 billion dollars in 1937 which is worth today 6.5 trillion.