The National Association of Professional Baseball Leagues, now known as Minor League Baseball, was organized when presidents of seven minor leagues met in Chicago on Sept. 5 and established rules of operation that generally remained through history. The NAPBL, national in scope, began play with 14 leagues and 96 teams in 1902.
Membership in the NAPBL grew to 41 leagues in a period of prosperity and stability, but raids from the outlaw Federal League and World War I were just around the corner. With the loss of manpower and wartime restrictions, only nine leagues were able to operate in 1918.
An agreement was signed which allowed a Major League team to own Minor League teams. Branch Rickey of the St. Louis Cardinals used this to establish the farm system, controlling players at different classifications of Minor League Baseball and developing them for his team.
The first night baseball game under permanent lights was played on May 2, a Western League game in Des Moines, IA, against Wichita. It attracted 12,000 fans for a team averaging 600. The idea spread quickly through the Minors and saved them during the depth of the Great Depression. Night games eventually spread to Major League baseball and revolutionized the industry.
Frank Shaughnessy invented playoff system. He came up with his idea to keep more teams in the race and sustain fan interest. It usually involved the first place team taking on the fourth place team, while second and third matched up in the other semifinal. Winners advanced to the title round.
Hall of Famer Joe DiMaggio, in his first pro season, hit safely in 61 straight games for San Francisco (Pacific Coast League). In 1941, he had a 56-game hitting streak for the New York Yankees, considered by many as the greatest batting feat in Major League history.
With players gone to serve their country and travel restrictions, only 10 Minor Leagues remained in operation.
Jackie Robinson made his debut in Minor League Baseball with Montreal (International League). The next season, Branch Rickey made Robinson the first African-American ever to play in the Major Leagues when he joined the Brooklyn Dodgers.
In the boom years after World War II, Minor League baseball spread to cities, towns and villages across the country. At the peak, there were 59 leagues with nearly 450 teams in operation. The all-time regular season attendance record of 39.7-million was set in 1949.
Emmett Ashford became the first African-American umpire in the Minor Leagues, working in the Southwestern International League.
Joe Bauman became the greatest home run hitter in pro baseball history, hitting 72 for Roswell (NM) in the Longhorn League, a record that stood until Barry Bonds hit 73 for San Francisco in 2001. Playing in just 138 games, Bauman hit .400 with 224 RBIs and 188 runs scored.
Bernice Gera worked a New York-Penn League game on June 24 to become the first female umpire in professional baseball. She resigned after one game and it was not until 1983 that Pam Postema became the first woman to work through the Minors and reach the top level of Class AAA.
Pawtucket and Rochester (International League) met in the longest professional baseball game ever played, 33 innings. It began on Apr. 18 and into the wee hours on Apr. 19 before it was suspended and finally completed on June 23.
The largest crowd in Minor League history, 65,666, watched an American Association game (and a giant fireworks show) at Denver's Mile High Stadium on July 4.
Baseball's Facilities Standards went into effect, setting minimum standards for Minor League ball parks and touching off the biggest building boom in history. More than half the teams in the Minors now play in stadiums built or completely renovated since that time.
The Buffalo Bisons of the American Association attracted 1,240,951 fans to set the all-time record for Minor League Baseball. The Bisons exceeded the one million mark six seasons (1988-93) in a row.
Minor and Major League baseball reached agreement on a 10-year contract to guarantee a Major League player development contract for all 160 teams through the life of the contract.
The NAPBL formally changed its name to Minor League Baseball, a name many both inside and outside the organization had been using for years.
Minor League Baseball honors its Centennial Season with a year-long celebration.