The American Association was formed by mid-western clubs who resented the National
League's ban on beer and Sunday baseball. Dominated by the St. Louis Browns
magnate Chris von der Ahe, the league thrived, quickly making peace with the NL.
However, the Players' League revolt undid the AA, which (on the advice of the NL)
expanded to 12 teams in 1890 to directly compete with the PL, a disastrous move that
exacerbated the ills of that strife-torn year and led to the AA's being absorbed
by the NL after the 1891 season.