The National Association of Base Ball Players (NABBP) was the first organization governing American baseball. (The sport was spelled with two words in the 19th century.) The first convention of sixteen New York City area clubs in 1857 effectively terminated the Knickerbocker era, during which the rules of the game were largely at the discretion of individual clubs. Besides governing the playing rules and its own organization, the Association established standards for official scoring (reporting), "match" play, a championship, amateurism, and the integrity of the contest (then known as hippodroming). Following trends in the evolution of the sport, in the 1869 season it accepted professionalism in its ranks. The last convention, held in 1871, with hundreds of members represented only via state associations, provoked the establishment of separate professional and amateur associations. The succeeding National Association of Professional Base Ball Players is considered the first professional sports league; through 1875 it governed professional baseball and practically set playing rules for all. Because the amateur successor never attracted many members and it convened only a few times, the NABBP is sometimes called "the amateur Association" in contrast to its professional successor. Growth Prior to the American Civil War (1861–1865), the beginnings of baseball competed for public interest with cricket and regional variants of baseball, notably town ball played in Philadelphia and the Massachusetts Game played in New England. In the 1860s, aided by the War, "New York" style baseball (as often played by Union Army troops passing the uneventful days of camp life between occasional skirmishes and battles) expanded through various corps, regiments, brigades, and other units into a national game. In addition, the parallel civilian NABBP, as its governing body, expanded into a true national organization, although most of the strongest clubs remained those based in New York City, Brooklyn and Philadelphia. By the end of 1865, almost 100 clubs were members of the "National Association" organization. By 1867, it had over 400 members, including some clubs from as far away as the Pacific Ocean west coast in San Francisco and south to the Gulf of Mexico coast in Louisiana. Because of this growth, regional and state organizations began to assume a more prominent role in the governance of the sport. Baseball's exploding popularity, however, was not confined to the NABBP organization, whose core lay in the vicinity of New York City; there were thousands of organized baseball clubs nationwide