http://ezinearticles.com/?The-Origin...all&id=1097991
Wu-YiSource.comPrior to 1845, the standardized rules for modern baseball did not exist. 1845 saw the formation of the New York Knickerbockers, a base ball club that gathered together to play a game that "they had been playing for some time" - most likely a game that had been invented by urban children of the time. Alexander Cartwright is officially recognized as the first to write down the modern rules of baseball, though is contested against for being called the inventor of baseball. He was part of the Knickerbockers base ball club, but it's entirely possible he was the secretary, as it's widely believed the rules were a group effort.
In 1857, sixteen clubs from New York City sent delegates to standardize the rules of baseball. It is agreed that they simply modified the original Knickerbockers rules.
1865 saw the ending of the Civil War, and with the return of prisoners of war saw the spread of baseball to other parts of the nation, where it quickly became popular.
The evolution of baseball as we know it today is debated by history experts and sports aficionados alike. Earliest mention of a baseball-like sport (a sport containing a bat, a ball, bases, or at least two of the three elements) being played are from the 1300s in Russia, but many variations on the idea are wide-spread. It is difficult to really track down the origins of the game, as most towns and villages had their own rules for it, mostly depending on what they had available to play with. A variation called "Cat and Dog" involved trying to get one stick - the "cat" - into a hole while the other stick - the "dog" tried to keep the cat from the hole by hitting it away. If the dog successfully batted the cat away, they would then try to get a ball into the hole.
Stool Ball was a game played in America as well as Europe, which involved a pitcher trying to hit a target with a ball, and a batter defending the target by batting the ball away. After successfully hitting the ball, the batter then runs between the bases to get to "home".
That baseball is based on English and Gaelic games such as cat, cricket, and rounders is difficult to dispute. For a time, people claimed the sport began in their country, but most of their supporting evidence was based largely on patriotism. Common theory is that there is no one origin of baseball, but rather that it is a culmination of bat, base and ball games played by children in urban settings where there were plenty of people of different origins coming together and sharing ideas.
"Vintage Baseball" - a game using the 1857 rules, modified from the Knickerbocker's rules, is still played today by hundreds of baseball clubs, some of which dedicate themselves to period reenactments by wearing the same style hats and uniforms as well as adopting the behaviors of the people of that era.
The very first all-pro baseball team was the Cincinnati Red Stockings, later called the Cincinnati Reds. It was founded as an amateur club in 1863, but became fully professional in 1869.
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http://en.wikipedia.org/wiki/Origins_of_baseball