Joaquin Fidel Romaguera was an American tenor and actor. A longtime performer with the New York City Opera from the 1960s through the 1980s, he notably created the role of Professor Risselberg in the world premiere of Gian Carlo Menotti's The Most Important Man in 1971. On Broadway he originated the role of Adolfo Pirelli in the original Broadway production of Stephen Sondheim's Sweeney Todd: The Demon Barber of Fleet Street (1979). He was nominated for the Drama Desk Award for Outstanding Featured Actor in a Musical for his portrayal of Teddy in the 1987 off-Broadway revival of Cole Porter's Gay Divorce. Other career milestones included portraying Nicolas Orsini in the world premiere of Alberto Ginastera's Bomarzo with the Opera Society of Washington, and appearing as Captain Pirzel in the United States premiere of Bernd Alois Zimmermann's Die Soldaten with conductor Sarah Caldwell and the Opera Company of Boston in 1982.

The Most Important Man is an opera in three acts with music and libretto by Gian Carlo Menotti. Commissioned by Julius Rudel for the New York City Opera, the work premiered at Lincoln Center in 1971 in a production directed by Menotti with sets designed by Oliver Smith and costumes by Frank Thompson. An opera focusing on racial tensions in Africa with a central black hero, the work was poorly received by most critics. However, Menotti personally believed that this was one of his best operas on par with The Consul and The Saint of Bleecker Street. The work's first European performance was at the Teatro Lirico Giuseppe Verdi in Trieste, Italy, on January 17, 1972. The opera uses Menotti's characteristic lyrical style which is inspired by Puccini and the Italian verismo opera tradition. In this work he infuses African percussion and rhythms, much in the way Puccini infused Asian inspired melodies and musical practices into his opera Madama Butterfly.