In 1946, after their massive success with Oklahoma! and Carousel, Hammerstein approached Rodgers with an idea for a different kind of musical that would focus on an ordinary person struggling to uphold his principles in the face of success in his field. As he wrote the book for Allegro for over a year, Hammerstein was pioneering new territory for American musical theatre – the “concept musical,” a whole new genre of the form, which would pave the way for such legendary hits as Cabaret, Hair, Company, The Threepenny Opera, A Chorus Line and Cats.

On October 10, 1947, crowds filtered into Broadway’s Majestic Theatre for the highly anticipated debut of Allegro, an intriguing musical that had dazzled and challenged critics and audiences alike throughout its legendary out-of -town tryouts in New Haven and Boston. Boasting the largest advance box office sales in Broadway history to date, Allegro was the talk of the town. The New York Post hailed it as “a distinguished musical play, beautiful, imaginative, original and honestly moving.” Brooks Atkinson of The New York Times compared the innovative show to an Our Town with music, later describing it as “a fragment of The American Legend.”

Allegro played 315 performances at the Majestic Theatre, closing in July of the following year as the highest-grossing show of its season.