Armida al campo d'Egitto is an opera in three acts by Antonio Vivaldi to a libretto by Giovanni Palazzo.
 It was first performed during the Carnival season of 1718 at the Teatro San Moisè in Venice.
 Vivaldi's version is different from the more than 50 operas whose themes derive in varying degrees from the story of Rinaldo and Armida in Torquato Tasso's epic poem "La Gerusalemme liberata" ("Jerusalem Delivered").
 Unlike the more than 50 operas based on the romance of Rinaldo and Armida, Vivaldi's version starts during previous events before the war against the Crusaders.
 Armida was revived for the Carnival season of 1738, with much of the music rewritten, and arias by Leonardo Leo added.
 Act II of the original version of the opera is now lost.
Rescue opera was a popular genre of opera in the late 18th and early 19th centuries in France and Germany.
 Generally, rescue operas deal with the rescue of a main character from danger and end with a happy dramatic resolution in which lofty humanistic ideals triumph over base motives.
 Operas with this kind of subject matter became popular in France around the time of the French Revolution; a number of such operas dealt with the rescue of a political prisoner.
 Stylistically and thematically, rescue opera was an outgrowth of the French bourgeois "opéra comique"; musically, it began a new tradition that would influence German Romantic opera and French grand opera.
 The most famous rescue opera is Ludwig van Beethoven's "Fidelio".
Adolf Čech (11 December 184127 December 1903) was a Czech conductor, who premiered a number of significant works by Antonín Dvořák (the 2nd, 5th and 6th symphonies, more than any other conductor; other important orchestral works, four operas, the "Stabat Mater"), Bedřich Smetana ("Má vlast", five operas), Zdeněk Fibich (two operas) and other Czech composers.
 He also led the first performances outside Russia of two operas by Pyotr Ilyich Tchaikovsky and the Czech premieres of seven operettas by Jacques Offenbach.
 He was also a bass singer and a translator of opera librettos.
Don Carlos is a five-act grand opera composed by Giuseppe Verdi to a French-language libretto by Joseph Méry and Camille du Locle, based on the dramatic play "Don Carlos, Infant von Spanien" ("Don Carlos, Infante of Spain") by Friedrich Schiller.
 The opera is usually performed in an Italian translation.
 In addition, it has been noted by David Kimball that the Fontainebleau scene and auto da fé "were the most substantial of several incidents borrowed from a contemporary play on Philip II by Eugène Cormon".
Pomone ("Pomona") is a pastoral opera in a prologue and five acts by Robert Cambert with a libretto by Pierre Perrin.
 It has been described as "effectively the first French opera."
 It was first performed in Paris at the Jeu de Paume de la Bouteille theatre belonging to Cambert and Perrin's Académie d'Opéra on 3 March 1671.
 The production had ballets choreographed by Des Brosses and sets and machinery designed by Alexandre de Rieux, marquis de Sourdéac.
 The novelty of the work drew large audiences and the opera enjoyed 146 performances over the eight months of its run.
 The score of "Pomone" has only partially survived.
Styled a "festa teatrale", "Le feste d'Apollo" consists of a prologue and three self-contained acts on the model of French "opéra-ballet" (the court of Parma was passionately interested in French culture).
 Gluck knew the Archduchess Maria Amalia well as she had sung in two of his operas, "Il Parnaso confuso" and "La corona", in Vienna.
 The composer recycled a lot of music from his earlier operas in the score of "Le feste".
 In fact, the whole of the third act, "Orfeo", is a shorter reworking of his most famous piece, "Orfeo ed Euridice" (1762).
 The overture to the prologue is taken from "Telemaco".
 Gluck later reused some of the choruses in two of the operas he wrote for Paris, "Iphigénie en Aulide" and "Iphigénie en Tauride".
Ruddigore; or, The Witch's Curse, originally called Ruddygore, is a comic opera in two acts, with music by Arthur Sullivan and libretto by W. S. Gilbert.
 It is one of the Savoy Operas and the tenth of fourteen comic operas written together by Gilbert and Sullivan.
 It was first performed by the D'Oyly Carte Opera Company at the Savoy Theatre in London on 22 January 1887.
Luciano Mariani (1801 – 10 June 1859) was an Italian operatic bass.
 Amongst the several roles he created were Rodolfo in Bellini's "La sonnambula" [Milan, Teatro Carcano, 1831], Alfonso d'Este in Donizetti's "Lucrezia Borgia" and Oroe in Rossini's "Semiramide".
 His elder sister, Rosa Mariani, was also an opera singer (contralto) and sang Arsace in the premiere of "Semiramide".
 They toured Italy singing together in many operas.
 Mariani sang in Lisbon at the Teatro São Carlos from 1839 to 1840, where he appeared in several Portuguese premieres of Italian operas, as well as the world premieres of Antonio Luís Miró's opera "Virginia" and Manuel Inocêncio Liberato dos Santos's opera "Inês de Castro".
 Mariani was born in Cremona and died in Castell'Arquato, aged 58.
Marie-Gabrielle Krauss (24 March 18426 January 1906) was an important 19th century Austrian-born French operatic soprano.
 She created major roles in operas by Anton Rubinstein, Charles Gounod, Camille Saint-Saëns, Auguste Mermet, Clémence de Grandval, Errico Petrella, Antônio Carlos Gomes and Émile Paladilhe.
 She also created roles in local premieres of Verdi and Wagner operas.
 Krauss was a leading soprano at the Paris Opera for 13 years, and also sang with great success in Italy and Russia.
Marie Wilt (also Maria Vilda and Marie Liebenthaler) (30 January 1833 – 24 September 1891) was an Austrian dramatic coloratura soprano.
 Possessing a wide vocal range with a significant amount of power and flexibility, Wilt sang a wide repertoire that encompassed the operas of Wolfgang Amadeus Mozart, the German operas of Richard Wagner, the grand operas of Giuseppe Verdi, and the bel canto operas of Bellini, Rossini, and Donizetti.
 She sang for many years at the Vienna Hofoper (now Vienna State Opera) and for a number of seasons at the Royal Opera House, Covent Garden in London.
 She notably portrayed the role of Sulamith in the world premiere of Karl Goldmark's "Die Königin von Saba" in 1875.
 Also a regular performer of the concert repertoire, Wilt often appeared in performances of works by Beethoven, Haydn, and Mendelssohn.

Question: Do the operas Don Carlos and Pomone have the same number of acts?
Answer: yes