The National Football League (NFL), which was founded in 1920, was preceded by the American Professional Football Association (APFA), which featured ten clubs from four different states and competed in local regional leagues.
The league changed to its current name in 1922. The NFL became the first professional football league to successfully establish a presence on a national basis after several decades of fruitless attempts.
The only two founding teams that are still competing in the league are the Decatur Staleys (now the Chicago Bears) and the Chicago Cardinals (now the Arizona Cardinals).
The Green Bay Acme Packers, established in 1919 (entered the NFL in 1921; currently known as the Green Bay Packers), are the oldest NFL team still operating in the same city.
As the league adopted ever more formal organization throughout the 1920s and 1930s, league membership eventually stabilized. In 1933, the inaugural championship match took place.
The NFL ceased signing black players in 1927, but after World War II, integration resumed. After the war, there were other changes. The position of league president changed into the more powerful position of commissioner, echoing a similar development in Major League Baseball.
The NFL was the first professional football league to effectively develop a presence on a national level.