The National Football League (NFL) was established in 1920 as the American Professional Football Association (APFA) before being renamed as the NFL in 1922. It is the highest professional level of American Football in the world, consisting of 32 teams divided equally into two conferences, the American Football Conference (AFC) and National Football Conference (NFC). The winner of each conference plays each other in the Super Bowl, one of the most watched sporting events of the year.
Champions were initially determined by end-of-season standings, but a playoff system was implemented in 1933 which saw winners crowned in the NFL Championship game before the Super Bowl was established in 1967.
With 13 titles, the Green Bay Packers are the most successful franchise in history, with nine NFL Championships before the Super Bowl era, and four Super Bowls afterwards. The New England Patriots and Pittsburgh Steelers have won the most of any franchise, with six each, since the introduction of the Super Bowl.
Tom Brady has won seven Super Bowls, giving him more titles than every NFL franchise, winning six with the Patriots and one with the Tampa Bay Buccaneers.
As well as being the most popular sports league in the US, the NFL is also the wealthiest sports league in the world by revenue and has the most valuable teams. The Super Bowl is the second most watched annual club sporting event, only behind the UEFA Champions League final.