actually played, matched up the Houston Oilers vs. the Green Bay Packers. It took a half-dozen more seasons for this idea to become a reality. In the mid-1960s, Lamar Hunt, owner of the AFL's Kansas City Chiefs, first used the term "Super Bowl" to refer to the AFL–NFL championship game in the merger meetings. Hunt later said the name was likely in his head because his children had been playing with a Super Ball toy; a vintage example of the ball is on display at the Pro Football Hall of Fame in Canton, Ohio. In a July 25, 1966, letter to NFL commissioner Pete Rozelle, Hunt wrote, "I have kiddingly called it the 'Super Bowl,' which obviously can be improved upon." The leagues' owners chose the name "AFL–NFL Championship Game", but in July 1966 the Kansas City Star quoted Hunt in discussing "the Super Bowl—that's my term for the championship game between the two leagues", and the media immediately began using the term. Although the league stated in 1967 that "not many people like it", asking for suggestions and considering alternatives such as "Merger Bowl" and "The Game", the Associated Press reported that "Super Bowl" "grew and grew and grew—until it reached the point that there was Super Week, Super Sunday, Super Teams, Super Players, ad infinitum". "Super Bowl" became official beginning with the third annual game. Roman numerals are used to identify each Super Bowl, rather than the year in which it is held, since the fifth edition, in January 1971. The sole exception to this naming convention tradition occurred with Super Bowl 50, which was played on February 7, 2016, following the 2015 regular season, and the following year, the nomenclature returned to Roman numerals for Super Bowl LI, following the 2016 regular season. After the NFL's Green Bay Packers 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 their NFL counterparts, though that perception changed when the AFL's New York Jets defeated the heavily-favored NFL contender Baltimore Colts in Super Bowl III in Miami. One year later, the AFL's Kansas City Chiefs defeated the NFL's Minnesota Vikings 23–7 in Super Bowl IV in New Orleans, which was the final AFL–NFL World Championship Game played before the merger. Beginning with the 1970 season, the NFL realigned into two conferences;