The Super Bowl was first played on January 15, 1967 as part of an agreement between the NFL and its younger rival, the American Football League (AFL) in which each league's championship team would play each other in an "AFL-NFL World Championship Game". After the leagues merged in 1970, the Super Bowl became the NFL's championship game, played between the champions of the league's two conferences: the American Football Conference (AFC) and the National Football Conference (NFC).

Since the NFL season extends into the New Year, the Super Bowl uses Roman numerals to identify each game, rather than the year it was held. For example, Super Bowl XLII, played in February 2008, was actually part of the 2007 season.

Origins

The Super Bowl was created as part of the merger agreement between the National Football League (NFL) and its competitive rival, the American Football League (AFL). After its inception in 1920, the NFL fended off several rival leagues before the AFL began play in 1960. The intense competitive war for players and fans led to serious merger talks between the two leagues in 1966, culminating in a merger announcement on June 8, 1966. One of the conditions of the AFL-NFL Merger was that the winners of each league's championship game would meet in a contest to determine the "world champion of football". According to NFL Films President Steve Sabol, then NFL Commissioner Pete Rozelle wanted to call the game "The Big One". During the discussions to iron out the details, AFL founder and Kansas City Chiefs owner Lamar Hunt had jokingly referred to the proposed interleague championship as the "Super Bowl". Hunt thought of the name after seeing his kids playing with a toy called a Super Ball.; the small, round ball is now on display at the Pro Football Hall of Fame in Canton, Ohio. The name was consistent with postseason college football games which had long been known as "bowl games." The "bowl" term originated from the Rose Bowl Game, which was in turn named for the bowl-shaped stadium in which it is played. Hunt only meant his suggested name to be a stopgap until a better one could be found. Nevertheless, the name "Super Bowl" became permanent.

After the NFL's Green Bay Packers convincingly won the first two Super Bowls, some team owners feared for the future of the merger. At the time, many doubted the competitiveness of AFL teams compared with NFL counterparts. That perception all changed with the AFL's New York Jets defeat of the Baltimore Colts in Super Bowl III in Miami. One year later, the AFL's Kansas City Chiefs defeated the NFL Minnesota Vikings 23-7 and won Super Bowl IV in New Orleans, the last World Championship game played between the champions of the two leagues. The game is played annually on a Sunday as the final game of the NFL Playoffs. Originally the game took place in early to mid-January following a 14-game regular season and playoffs. Over the years the date of the Super Bowl has progressed from the second Sunday in January, to the third, then the fourth Sunday in January; the game is now played on the first Sunday in February, given the current 17-week (16 games and one bye week) regular season and three rounds of playoffs. This progression of the date of the Super Bowl has been caused by the following: the expansion of the NFL regular season in 1978 from 14 games to 16, the expansion of the pre-Super Bowl playoffs from two rounds to three (also in 1978), the addition of the regular season bye-week in the 1990s, and the decision prior to the 2003 season to start the regular season the week after Labor Day, moving the start of the season to a week later than it had been (in 1997, for example, the regular season started on Sunday, August 31). Former NFL commissioner Pete Rozelle is often considered the mastermind of both the merger and the Super Bowl. His leadership guided them into the merger agreement and cemented the preeminence of the Super Bowl.