The Chicago Symphony Orchestra (CSO), based in Chicago, was formed by Theodore Thomas in 1891. The Symphony makes its home at Orchestra Hall in Chicago and plays a summer season at the Ravinia Festival. The music director is Riccardo Muti, who began his tenure in 2010. The CSO is one of five American orchestras commonly referred to as the "Big Five". The Symphony makes its home at Orchestra Hall in Chicago and plays a summer season at the Ravinia Festival. Since Thomas, the orchestra has had ten music directors, including Rafael Kubelík, Fritz Reiner, Sir Georg Solti and Daniel Barenboim. From 2010 to the present, the incumbent conductor is Riccardo Muti. In 1890 Charles Norman Fay, a Chicago businessman, invited Theodore Thomas to establish an orchestra in Chicago. Under the name "Chicago Orchestra," the orchestra played its first concert October 16, 1891 at the Auditorium Theater. It is one of the oldest orchestras in the United States, along with the New York Philharmonic, the Boston Symphony Orchestra and the Saint Louis Symphony Orchestra.