The cornerstone of Major League Baseball has been the leagues and their teams. The majors are comprised of the National League, which dates back to 1876, and the American League, which became a major operation in 1901. The NL was itself predated by the National Association of Professional Base Ball Players (1871–75), which was arguably the fi rst major league. The NL itself operated in conjunction with the American Association, a major league from 1882 to 1891, and was rivaled by the short-lived Union Association in 1884 and the Players’ League in 1890. Since then the only other league to proclaim itself a major league was the Federal.
