Jeanne and Rex Sinquefield have donated $250,000 to underwrite the St. Louis Symphony’s hosting of the League of American Orchestras 68th conference, Imagining 2023, to be held in St. Louis June 18-20. This the first time St. Louis has hosted the League of American Orchestras Conference since 1966, and it is expected to bring hundreds of orchestra administrators, volunteers and musicians from across the country for three days of concerts, meetings and symposiums.