s baseball clubs became skilled at the game the competitiveness of the clubs resulted in many great base ball matches. These all-star matches drew many observers and as the sport increased in popularity so did the attendance. Once it was established that these matches were worthy of an admission fee, professionalism eventually took over the base ball community. One year after the demise of the first openly professional base ball club, the 1869–1870 Cincinnati Red Stockings, the National Association of Base Ball Players became the first professional base ball league in the United States. As poorly and unorganized as this league was, the opportunity for future investors as another avenue of income would lead to the formation of four more professional leagues in the next 15 years.
The first base ball convention was held in New York City on January 22, 1857 and was attended by 15 clubs, all from New York. Daniel "Doc" Adams was elected convention president and also was elected to head the Committee on Rules and Regulations. Revisions to the original 20 "Knickerbocker Rules" were made.
On March 10, 1858 another convention was held in New York. During this convention the National Association of Base Ball Players was formed and a committee to draft a constitution and by-laws was appointed. William H. Van Cott, who was the founder and president of the Gotham Club, was elected President. All 22 teams that attended were from New York.
The second annual National Association of Base Ball Players convention held in New York City in 1859 included teams from New Jersey. Membership grew to 49 clubs. In 1860 the annual N.A.B.B.P. convention held in New York City reported the membership at 62 clubs.
With the advent of the Civil War the membership of the annual conventions declined to as low as 28 in 1863 but following the war ballooned to 202 members in 1866.
As the game gained interest the move toward professionalism produced the first openly professional club, the 1869 Cincinnati Red Stockings. In previous years many teams secretly paid players, there were rumors of fixed games and the fans wagering before and during matches eventually won out over the "gentlemen's club" theory and the National Association of Professional Base Ball Players was formed on March 17, 1871 in New York City.
The new professional league included the following teams: Boston Red Stockings, Chicago White Stockings, Cleveland Forest Cities, Fort Wayne Kekiongas (Indiana), New York Mutuals, Philadelphia Athletics, Rockford Forest Cities (Illinois), Troy Unions (New York) and Washington Olympics. The first game was played at Hamilton Field in Fort Wayne, Indiana. Fort Wayne beat the club from Cleveland 2-0, but would not finish the season and would later be replaced by the Eckfords of Brooklyn.
The National Association lasted until 1875. Only three of the original nine teams would play all five seasons: Boston Red Stockings, New York Mutuals and the Philadelphia Athletics. In its short existence 18 new teams were admitted. With many teams not completing their schedules, allegations of fixed games, poor attendance, league mismanagement and the unbeatable club from Boston, the league folded.
On February 2, 1876, William Hulbert, the President of the Chicago White Stockings, who competed in the final two National Association seasons, spearheaded a meeting in New York City to organize a new more stable league. The National League was born and has been active ever since. The charter member teams were; Boston Red Caps, Chicago White Stockings, Cincinnati Red Stockings, Hartford Dark Blues, Louisville Grays, New York Mutuals, Philadelphia Athletics and St. Louis Brown Stockings.