High Quality Content by WIKIPEDIA articles! The Saint Louis Symphony Orchestra (SLSO) is an American symphony orchestra based in St. Louis, Missouri. Founded in 1880 by Joseph Otten as the St. Louis Choral Society, the SLSO is the second-oldest symphony orchestra in the United States as it is preceded by the New York Philharmonic. The St Louis Choral Society performed in the auditorium of the St. Louis Mercantile Library at Locust and Broadway in Downtown St. Louis. During the 1881-82, season the 80-member chorus was joined by an orchestra of 31 members. A disbanded Musical Union joined the group. In 1893 the St. Louis Choral-Symphony was formally incorporated. It remained largely a choral organization through its performances at the 1904 World's Fair under Alfred Ernst when it expanded to a 200-member chorus and an orchestra of 55. Under Max Zach's tenure (1907 to 1921), it changed its name to the St Louis Symphony Orchestra.