Known as America’s favorite pastime, the game of baseball as we know it originated in the 18th century. The documented, first known occurrence of a baseball-like game from 1791 shows New York Knickerbockers as the first team to play under modern baseball rules, beginning in 1845. The Knickerbockers invented the rule that required field players to tag the runner with the ball for an out. Previously, baseball players could oust a runner from the game by hitting him with a thrown ball.
About a decade after the Knickerbockers were formed, the club joined with 15 other New York teams and formed the National Association of Base Ball Players (NABBP) in 1857.
By 1867, more than 400 teams were a part of the organization, from states as far away as California. The inception of the NABBP established baseball as a national sport, and as more teams popped up around the country, the association started to shy away from the purely amateur category under which it previously worked. A professional grouping was instituted in the NABBP, although the organization later separated to form amateur and major leagues.
During this time, in the late 1800s, many associations strived to become a national baseball league. Many of these groups lasted for one or two seasons, though the National Association of Professional Baseball Leagues (what we now know as Minor League Baseball) established the first World Series in 1903.
After the founding of a professional league, baseball rose in popularity throughout the country. The 20th century brought new teams from all over the country, and many rising stars and teams have won national and world championships in a sport established many years ago for amateur play.