Being familiar with major league baseball history can add another dimension of excitement to the game. Baseball is one of the oldest sports in the US, and also one of the most popular, being called “America’s pastime.” Whether you’re traveling to an away baseball stadium or you’re watching a baseball game on television, knowing the history of baseball stadiums and baseball players can help you to realize the richness in the history of baseball.

The first professional baseball organization started up in the 1860s. Its popularity waned during the Civil War but it became more prominent with the beginning of the National Association of Baseball Players (NABBP).

The Brooklyn Atlantics dominated the NABBP while it was the primary professional baseball league, winning seven championships.

The NABBP grew to include over 400 clubs from all over the US. Some of these clubs persevered, evolving and remaining professional baseball clubs today. But a dispute over the nature of amateur and professional clubs caused the league to fold in 1871. From its ashes came the National Association of Professional Base Ball Players, which eventually evolved into the present-day National League.

Before the World Series decided which team should be considered the best in baseball, the best team was simply the National Association of Professional Base Ball Players team that had the best record. Then the American Association formed in 1884, and the top team from both the National League as well as the American Association would play each other to determine which was better. These early "world series" were somewhat different from the modern version, and they twice ended in a tie.

After the American Association dissipated in 1891, some changes were made to the way the World Series was played. For example, the league pennant was given to the team with the best record, rather than having a divisional playoff system. This lasted until 1969, when the ALCS and NLCS were first played.

It wasn’t until 1903 that the first real World Series was played, even though the American League formed in 1901. During the American League's first two years, the National and American Leagues were busy concentrating on who was better, without the World Series title to prove it. The 1903 World Series was played between the pennant winners, the Pittsburgh Pirates of the National League and the Boston Americans (now the Boston Red Sox) of the American League. The Boston American won the series five games to three. Immortal pitcher Cy Young pitched for Boston in this series.

Other professional baseball leagues started after the NABBP, including several black baseball clubs. These Negro Leagues, as they were called, included the Negro National League and the Eastern Colored League. The Negro National League lasted only about a decade. These clubs were necessary because of the baseball color line, an unwritten rule in Major League Baseball which prohibited African Americans, Hawaiians, Hispanics and Native Americans from playing in the Major Leagues. It wasn’t until 1947 that black men were a part of Major League Baseball, when Jackie Robinson joined the Brooklyn Dodgers. In 1948, due to financial hardships, the Negro Leagues ended altogether.

Free agency was only introduced to MLB in 1975. Baseball players attempted to win free agency for themselves, and leave behind the reserve clause, which essentially bound them to one club for life, before 1975. It wasn’t until players Andy Messersmith and Dave McNally went to arbitration with Major League Baseball that free agency became a part of the sport.

The designated hitter has been a controversial rule in Major League history. It originated as a way to speed up the game as well as to improve the quality of batters for spectators. The first designated hitter was used in 1973. It was Ron Blomberg of the New York Yankees; he was walked by Boston Red Sox pitcher Luis Tiant.

The Baseball Players Union governed the rights of baseball players, becoming quite a force in the 1960s. They led strikes in 1972, 1981 and 1994. The 1994 strike actually led to a unification of union administration between the National League and the American League.

Today, the National League and American League continue to play one another in the World Series.