↑ “The Commissionership: A Historical Perspective”. MLB.com. MLB Advanced Media. Truy cập ngày 11 tháng 3 năm 2016. The strength of the American League grew as an increasing number of National League players opted for the higher salaries offered by the new association. Faced with the prospect of losing many of its best players, the NL chose peace and declared the AL its equal in 1903. This led to a new National Agreement and the birth of the World Series. The American and National Leagues were established as major leagues and all other associations comprised the minor leagues, which fell under the jurisdiction of the National Association of Professional Baseball Leagues.
