Although soccer began as a demonstration sport,  the World Championship of soccer was the Olympics. The winners were the World Champions. In 1908 soccer became an official Olympic event. After the First World War,  more and more players turned professional. The better teams could not complete. Still, countries fielded professionals under the guise of being amateurs.

Athens 2004 goes August 13 to August 27. Here's a list of Men's Olympic Champions.