Originally established in 1920 as the American Professional Football Association, the National Football League is the highest level of gridiron football on the planet.
After enjoying a pro football monopoly, for several decades, the NFL received a strong challenge from the American Football League beginning in 1960. With teams in states across the country, from New York to California, the AFL grew in popularity prior to merging with the NFL in 1966.
Following many twists and turns, plus a few legal battles, Tex Schramm (NFL) and Lamar Hunt (AFL) led the way to the merger agreement between the rival leagues.