* The circus has long been a part of the theatre tradition. In the early days of Broadway, from the late nineteenth century through to the early twentieth, vaudeville and burlesque, themselves estranged cousins of the circus, dominated the New York entertainment scene. When film emerged as a cheaper alternative to live amusements and freak shows in the 1920s and 30s, the vaudeville circuit faced its demise; focus shifted instead to musical revues and light musical fare, including the shows of Rodgers and Hart, Cole Porter and Jerome Kern, which eventually morphed into the modern American musical thanks in part to works like Show Boat and Oklahoma!.