Usage of the phrase in baseball started with organization of championship series between the National League and the earlier American Association in the 1880s, later to be known as the World Series. Major League Baseball later set up the World Baseball Classic, a quadrennial international competition, in an effort to crown a true world champion. By the 1950s, the phrase "World Champions" was also being used by the newly formed NBA. The Super Bowl, the interleague championship between the NFL and American Football League, was explicitly named a "World Championship Game" for its first iteration.