National Football League: The first decade
1920: American Professional Football Association formed in Canton, Ohio, with 14 teams: Canton Bulldogs, Cleveland Tigers, Dayton Triangles, Akron Pros, Rochester Jeffersons, Rock Island Independents, Muncie Flyers, Decatur Staleys, Chicago Cardinals, Buffalo All-Americans, Chicago Tigers, Columbus Panhandlers, Detroit Heralds and Hammond Pros.
1921: League adds eight teams, including Green Bay Packers.
1922: APFA becomes the National Football League. Chicago Staleys become the Chicago Bears.
1925: Five new franchises admitted, including the New York Giants.
1926: Duluth Eskimos, featuring Ernie Nevers, joined NFL
1928: Nevers retired from pro football and Duluth was disbanded. NFL reduced to 10 teams
1929: Nevers returned to the NFL with the Chicago Cardinals. He rushed for six TDs and four PATs in a 40-6 victory over the Bears. His 40 points in one game remains an NFL record.