The game between the NFL and AFL champions was initially dubbed the "AFL-NFL World Championship." The term remained in use until the fourth championship game between the two leagues. In 1970, the NFL's Minnesota Vikings faced the AFL's Kansas Chiefs. In 1963, Lamar Hunt relocated the Texans from Dallas to Kansas City. He is known for creating the original idea of a championship game between the NFL and AFL champions.
The first three AFL-NFL Championship Games were played at the same location (Superdome in New Orleans) and used the same scheduling format as the regular season. The only difference was that the winner of each conference would play in the Super Bowl. The winners were determined based on winning the National Football League (NFL) and American Football League (AFL) championships.
In 1969, the NFL and AFL agreed to merge their organizations into one league with a single set of rules. The new league was called the "National Football League" (NFL). The existing AFL champion would be invited to join the newly formed NFL, while the remaining teams would form a new division within the NFL called the "American Football Conference" (AFC). The Super Bowl trophy was redesigned at this time to more accurately reflect what had happened during the season - including multiple team changes - rather than just showing the name of the winning club.
The first official NFL-AFL Championship Game was played in 1971 at Miami Stadium in Miami Gardens, Florida.
Following the merger of the NFL and the American Football League in 1970, the inaugural AFC Championship Game was held following the regular season. The game is regarded the successor of the previous AFL Championship, and its game results are included in the annual NFL Record and Fact Book with those of its predecessor. The merged league's championship was to be determined by a two-game series, with the winner going on to face the National Football Conference (NFC) champion in the Super Bowl. However, due to the poor quality of play in the first ever postseason game, it was decided that more research was needed into the effects of cold weather on football. As a result, the decision was made to postpone the championship series until January 1971 at which time a new system would be put in place.
The 1971 NFL Championship Game served as a final trial period for the new format before it was decided whether or not to continue with it. On February 3, 1971, the NFL announced that they were cancelling their planned championship game scheduled for January 1968. Instead, the top seed in each conference will be given a free pass to the Super Bowl while the No. 4 seed will be forced to play a qualifying round called the "Playoff Game" against either the No. 1 or No. 2 seed from the other conference. The winners of these games will travel to New York City where the Super Bowl will be played.
While the leagues maintained separate schedules until 1969, they agreed to conduct an annual AFL-NFL World Championship Game beginning in January 1967 and a joint draft beginning in 1967. Preseason games would be played between clubs from each conference beginning in 1967. The two conferences would alternate playing host to the championship game.
The NFL and AFL merged prior to the 1970 season. The 1970 merger created a single 16-game regular season that included both former AFL and current NFL teams. The merged league retained the NFL's existing division structure: East Division and West Division.
In 2002, the NFL realigned its divisions into North and South. This change was made so that each team would have an equal chance of qualifying for the playoffs. Prior to the 2002 season, the NFC had only four teams while the AFC had five teams. This rule was put in place to prevent one division with more teams than another division.