Question: What is an opera in by Vincenzo Bellini, Simon Boccanegra or I puritani ?
Context: Hexaméron, Morceau de concert S.392 is a collaborative composition for solo piano.  It consists of six variations on a theme, along with an introduction, connecting interludes and a finale.  The theme is the "March of the Puritans" from Vincenzo Bellini's opera "I puritani". I puritani ("The Puritans") is an opera in by Vincenzo Bellini.  It was originally written in two acts and later changed to three acts on the advice of Gioachino Rossini, with whom the young composer had become friends.  The music was set to a libretto by Count Carlo Pepoli, an Italian émigré poet whom Bellini had met at a salon run by the exile Princess Belgiojoso, which became a meeting place for many Italian revolutionaries. Catania–Fontanarossa Airport (Italian: "aeroporto internazionale Vincenzo Bellini di Catania-Fontanarossa" , English: Catania International Airport) (IATA: CTA, ICAO: LICC) also named as Vincenzo Bellini Airport, is an international airport 2.3 NM southwest of Catania, the second largest city on the Italian island of Sicily.  It is named after the opera composer Vincenzo Bellini who was born in Catania. La sonnambula "(The Sleepwalker)" is a ballet by the co-founder and ballet master of New York City Ballet, George Balanchine, made to Vittorio Rieti's music using themes from the operas of Vincenzo Bellini including "La Sonnambula", "Norma", "I Puritani" and "I Capuleti e i Montecchi" (1830–35) and with costumes by Karinska.  The premiere took place with the Ballet Russe de Monte Carlo on Wednesday, 27 February , at City Center of Music and Drama, New York; the City Ballet premiere was on 6 January 1965. Simon Boccanegra (] ) is an opera with a prologue and three acts by Giuseppe Verdi to an Italian libretto by Francesco Maria Piave, based on the play "Simón Bocanegra" (1843) by Antonio García Gutiérrez, whose play "El trovador" had been the basis for Verdi's 1853 opera, "Il trovatore". "La danza" (1835) is a patter song by Gioachino Rossini, in Tarantella napoletana time, the eighth song of the collection "Les soirées musicales" (1830–1835).  The lyrics are by Count Carlo Pepoli (), librettist of Vincenzo Bellini's opera "I puritani".  "La danza" is a stand-alone chamber vocal piece, rather than part of a larger work. Rossini had influenced the management of the Théâtre-Italien to commission works by the outstanding Italian composers of the day—Donizetti and Vincenzo Bellini.  Both wrote operas for that house in Paris, Bellini's contribution being the hugely-successful "I puritani".  Donizetti's opera, which premiered on 12 March 1835 (a few months after "I puritani") was not nearly as much of a success.  However, it marked Donizetti's first opera to have its premiere in Paris. The Proscribed Royalist, 1651 (1853) is a painting by John Everett Millais which depicts a young Puritan woman protecting a fleeing Royalist after the Battle of Worcester in 1651, the decisive defeat of Charles II by Oliver Cromwell.  The Royalist is hiding in a hollow tree, a reference to a famous incident in which Charles himself hid in a tree to escape from his pursuers.  Millais was also influenced by Vincenzo Bellini's opera "I Puritani". Count Carlo Pepoli (22 July 1796 – 7 December 1881) was an Italian politician and journalist.  He was also acclaimed as a poet, his most well-known work being the libretto for Vincenzo Bellini's final opera, "I puritani" which was given its premiere in Paris in January 1835. Rolando Panerai (born 17 October 1924) is an Italian baritone, particularly associated with the Italian repertory.  He was born in Campi Bisenzio, near Florence, Italy and studied with Frazzi in Florence and Armani and Giulia Tess in Milan.  Panerai made his stage debut in 1947 in Naples at the Teatro di San Carlo as the pharaon in Rossini's "Mosè in Egitto".  Other debuts, both in 1951, were as Simon Boccanegra in "Simon Boccanegra" in Bergamo and as Sharpless in "Madama Butterfly" at La Scala in Milan.  He sang in many rarely performed Verdi operas on radio broadcast for RAI in 1951 (to commemorate the 50th anniversary of Verdi's death), such as "Giovanna d'Arco", "La battaglia di Legnano", and "Aroldo".  Later roles included most of the great Verdi baritone roles, particularly the title character in "Rigoletto", The Count of Luna in "Il trovatore", Giorgio Germont in "La traviata", Marquis of Posa in "Don Carlos", Amonasro in "Aida".
Answer: I puritani