Throughout its history, the National Football League and other leagues have used several different formats to determine their league champion, including a period of interleague match-ups determining a true world champion.
The NFL first determined champions through end-of-season standings, but switched to a playoff system in 1933. The rival All-America Football Conference and American Football League, which have since merged with the NFL (some AAFC teams in 1950, but because of a problem with the NFL-AAFC merger, AAFC championships games and records don't count in NFL record books. The AFL begun play in 1960 and used an playoff system to determine its champions like the league it was rivaling at time of formation.
From 1966–1969 prior to the AFL-NFL merger in 1970, the NFL and the AFL agreed to hold an ultimate championship game, first called the AFL-NFL World Championship game and later renamed the Super Bowl after 1968. The most important factor of the merger was the fact that the all ten AFL teams joined the NFL in 1970 and every AFL championship game and record count in NFL record books. Since the merger, the NFL has become the only major professional football league in the United States. The Super Bowl was originally a game between the AFL and the NFL but after the merger, the Super Bowl was retooled as the NFL's championship game. The old NFL Championship game became the NFC Championship Game, while the old AFL Championship became the AFC Championship Game. The NFL lists the old AFL/NFL championship games with 'new' AFC/NFC championship games in its record books.
The Green Bay Packers are the most successful franchise, winning 13 titles during the NFL's entire history. Green Bay also holds the distinction of winning the most NFL titles pre-Super Bowl era with nine. Green Bay last won the NFL Championship in 2010 when it beat the Pittsburgh Steelers in Super Bowl XLV, claiming a 31-25 victory. However, if only the Super Bowl era is considered, the Steelers hold the record for most Super Bowl wins with a total of six Super Bowl championship victories.
