The first National League season opened on April 22, 1876 with eight teams, including a few holdovers from the National Association. Hulbert's White Stockings stole away some of the best National Association players and quickly became the new league's powerhouse. Chicago won 52 of its 66 games in the 1876 season. The last place Cincinnati Red Stockings went 9–56 [source: Nemec].
The National League (NL) introduced some new rules to the game that survive today. In the NL, batters had to remain in the batter's box when swinging, and runners could take an extra base if a fielder obstructed their path. One rule that didn't change initially was the prohibition against a called third strike. Umpires had to warn a player who failed to swing at a "good ball" that would have been the third strike. If the player persisted, then he could be called out [source: Nemec].
The American Association, a rival professional league, launched in 1882, appealing to a more working class crowd with 25-cent admissions and alcohol at games. The champions of the National League and American Association played each other in 1882 in what some call the first "World Series." In 1891, the two rival leagues merged into a single 12-team National League, also known as the "Senior Circuit" [source: Miklich].
The American League (AL), known as the "Junior Circuit," formed in 1901 and its Boston Pilgrims won the first official World Series in 1903 [source: Major League Baseball]. In the history of the World Series, the AL leads with 62 wins to 43. The biggest contributor to the AL's dominance is the New York Yankees with 27 World Series titles. In distant second come the NL's St. Louis Cardinals with 11 titles [source: MLB.com].
Today, there are 16 teams in the National League, although that number will reduce to 15 when the Houston Astros switch to the AL in 2013. The only major difference between AL and NL baseball is the designated hitter rule adopted by the AL in 1973 [source: McKelvey]. (The rule allows AL teams to substitute a batter for the pitcher during at-bats, since pitchers are typically such weak hitters.) National League teams complain that the rule gives the AL squads an unfair advantage in the World Series when the DL rule is in effect at AL ballparks. Despite pressure to adopt the rule, there is no talk among NL managers to change course [source: Verducci].
Now let's take a closer look at those original eight teams that joined the fledgling National League back in 1876.