NFL history

The National Football League (NFL) was founded in 1920 as the American Professional Football Association (APFA) with ten teams from four states, all of whom existed in some form as participants of regional leagues in their respective territories; it took on its current name in 1922. The NFL was the first professional football league to successfully establish a nationwide presence, after several decades of failed attempts. Only two teams currently in the NFL, the Decatur Staleys (now the Chicago Bears) and the Chicago Cardinals (now the Arizona Cardinals), are founding members. The Green Bay Packers, founded 1919 (joined the NFL in 1921), is the oldest NFL franchise in continuous operation with the same name in the same location.

League membership gradually stabilized throughout the 1920s and 1930s as the league adopted progressively more formal organization. The first official championship game was held in 1933. The NFL stopped signing black players in 1927 but reintegrated in 1946 following World War II. Other changes followed after the war; the office of league President evolved into the more powerful Commissioner post, mirroring a similar move in Major League Baseball. Teams became more financially viable, the last team folding in 1952 and the league absorbing teams from the briefly more successful All-America Football Conference in 1950, two of which survive to the present day. By 1958, when that season's NFL championship game became known as "The Greatest Game Ever Played", the NFL was on its way to becoming one of the most popular sports leagues in the United States.

...
Wikipedia