This is the VOA Special English Economics Report.

With oil around one hundred dollars a barrel, this may be a good time for a short history of petroleum.

Petroleum has been important since ancient times. The Greek historian Herodotus told of its use in the form of pitch for building and road making in the ancient city of Babylon in present-day Iraq.

In Latin, the name means "rock oil." Petroleum is a fossil fuel. The liquid comes from the remains of plants and animals that died millions of years ago. These remains were buried deep below levels of rock over time and under great pressure.

This geological process created complex molecules of hydrogen and carbon. Oil can also contain other elements. Crude oil, or unprocessed petroleum, is called sour when it contains a lot of sulfur, an impurity. Sour crude requires more refining than sweet crude, which is low in sulfur and, as a result, often more valuable.

The modern history of oil started in the middle of the eighteen hundreds. At that time, a method was found to make kerosene fuel from petroleum. This kind of fuel became popular for heating and lighting.

Edwin Drake drilled the first oil well in the United States in eighteen fifty-nine near Titusville, Pennsylvania.

In the early eighteen sixties, John D. Rockefeller entered the oil business. Rockefeller and his partners understood the power of controlling all levels of production. By eighteen seventy, Rockefeller and his partners formed the Standard Oil Company.

Standard Oil and other companies that it owned performed every level of production -- from drilling to refining to transporting and selling. But in its efforts to grow, Standard Oil was strongly criticized for crushing smaller competitors.

Finally, in nineteen eleven, the United States Supreme Court ruled that Standard Oil was misusing its powerful market position. The ruling divided Standard Oil into thirty-four independent companies.

Today, ExxonMobil, ConocoPhillips and Chevron are some of the companies whose roots go back to the breakup of Standard Oil. They are among the largest publicly traded companies in the world.