For several years, the National League and American Association champions met in a postseason championship series—the first attempt at a World Series.
The Union Association survived for only one season (1884), as did the Players League (1890), an attempt to return to the National Association structure of a league controlled by the players themselves.
An unknown number of African-Americans played in the major leagues as Indians, or South or Central Americans.
And a still larger number played in the minor leagues and on amateur teams as well.
Both leagues are considered major leagues by many baseball researchers because of the perceived high caliber of play (for a brief time anyway) and the number of star players featured.
However, some researchers have disputed the major league status of the Union Association. Louis club, which was deliberately "stacked" by the league's president (who owned that club), was the only club that was anywhere close to major league caliber.
The first and most prominent professional club of the NABBP era was the Cincinnati Red Stockings.
In the majors, however, it was not until Robinson (in the National League) and Larry Doby (in the American League) emergence that baseball would begin to remove its color bar.
The early years of the National League were nonetheless tumultuous, with threats from rival leagues and a rebellion by players against the hated "reserve clause", which restricted the free movement of players between clubs.
Many leagues, including the venerable Eastern League, survived in parallel with the National League.
One, the Western League, founded in 1893, became aggressive.
Clubs now had the ability to enforce player contracts, preventing players from jumping to higher-paying clubs.