Baseball evolved from cricket in the early to mid 1800's. Then a man named Abner Doubleday "invented baseball" closer to the mid 1800's.
Baseball was developed from an earlier game called rounders. The earliest reference we have to baseball dates to 1744. One of the earliest references in literature was in Jane Austen's Northanger Abbey, probably written before 1800, in which the heroine is described as liking to play baseball.
At first, the rules were not codified, but would be agreed upon before a game. There is a story that Abner Doubleday invented baseball in 1839, and it is possible he wrote some codification at that time, but historians seem to regard his invention of baseball as a myth. The oldest codification we have was by Alexander Cartwright of the New York Knickerbockers, in 1845.
Baseball associations became very important by 1850 in some areas of the United States, notably New York. Leagues and associations of clubs started to develop in 1857. The game was further spread during the Civil War, as a pastime for the soldiers.
The oldest major league is the National League, which was formed in 1875, and its formation is important because it had formal rules that had been absent earlier. The American League evolved from the earlier Western League about the turn of the 20th century. In 1903, the two leagues formalized relations with each other, and the World Series began to be played
There is a link below to a source article, which provides more detail.
In the mid-1850s, a baseball craze hit the New York metropolitan area. By 1856, local journals were referring to baseball as the "national pastime" or "national game". A year later, sixteen area clubs formed the sport's first governing body, the National Association of Base Ball Players. In 1863, the organization disallowed putouts made by catching a fair ball on the first bounce. Four years later, it barred participation by African Americans. The game's commercial potential was developing: in 1869 the first fully professional baseball club, the Cincinnati Red Stockings, was formed and went undefeated against a schedule of semipro and amateur teams. The first professional league, the National Association of Professional Base Ball Players, lasted from 1871 to 1875; scholars dispute its status as a major league.
Major League Baseball is an American sport. It involves hitting a ball with a bat. The American League and the National League merged in 2000. The origins of the game are unclear, but it became a major sport from the 1860s onwards.
What is the history behind the salary cap in the MLB?
Paul G. Zinn has written: 'The major league pennant races of 1916' -- subject(s): Major League Baseball (Organization), Baseball, History 'The major league pennant races of 1916' -- subject(s): Baseball, History, Major League Baseball (Organization)