The National Association of Base Ball Players (NABBP) was the first organization governing American baseball (spelled as two words in the 19th century).
The first convention of 16 New York City area clubs was held at Smith's Hotel, 462 Broome Street in January 1857. One delegate from each club had previously been assigned to a committee, whose task was to draw up a set of regulations governing the game. Their report was adopted at the final meeting of the convention on February 25, effectively bringing to an end the Knickerbocker era, when games were played under rules largely at the discretion of individual clubs.