Falstaff (] ) is an opera in three acts by the Italian composer Giuseppe Verdi (18131901).
 The libretto was adapted by Arrigo Boito from Shakespeare's "The Merry Wives of Windsor" and scenes from "Henry IV", parts "1" and "2".
 The work premiered on 9 February 1893 at La Scala, Milan.
L'Orfeo (SV 318) (] ), sometimes called La favola d'Orfeo ] , is a late Renaissance/early Baroque "favola in musica", or opera, by Claudio Monteverdi, with a libretto by Alessandro Striggio.
 It is based on the Greek legend of Orpheus, and tells the story of his descent to Hades and his fruitless attempt to bring his dead bride Eurydice back to the living world.
 It was written in 1607 for a court performance during the annual Carnival at Mantua.
 While Jacopo Peri's "Dafne" is generally recognised as the first work in the opera genre, and the earliest surviving opera is Peri's "Euridice", "L'Orfeo" is the earliest that is still regularly performed.
Arrigo Boito (] ; 24 February 1842 10 June 1918) (whose original name was Enrico Giuseppe Giovanni Boito and who wrote essays under the anagrammatic pseudonym of Tobia Gorrio), was an Italian poet, journalist, novelist, librettist and composer, best known today for his libretti, especially those for Giuseppe Verdi's operas "Otello" and "Falstaff", and his own opera "Mefistofele".
 Along with Emilio Praga, and his own brother Camillo Boito he is regarded as one of the prominent representatives of the Scapigliatura artistic movement.
Mefistofele (] ) is an opera in a prologue, four acts and an epilogue, the only completed opera with music by the Italian composer-librettist Arrigo Boito (there are several completed operas for which he was librettist only).
 The opera was given its premiere on 5 March 1868 at La Scala, Milan, under the baton of the composer, despite his lack of experience and skill as a conductor.
Nerone (Nero) is an opera in four acts composed by Arrigo Boito, to a libretto in Italian written by the composer.
 The work is a series of scenes from Imperial Rome at the time of Emperor Nero depicting tensions between the Imperial religion and Christianity, and ends with the Great Fire of Rome.
 Boito died in 1918 before finishing the work.
Amleto is an opera in four acts by Franco Faccio set to a libretto by Arrigo Boito, based on Shakespeare's play "Hamlet".
 It premiered on 30 May 1865 at the Teatro Carlo Felice in Genoa and was revised for a La Scala production given on 12 February 1871.
Inno delle nazioni (Hymn of nations), a cantata in a single movement, is one of only two secular choral works composed by Giuseppe Verdi.
 This Hymn incorporates "God Save the King", "La Marseillaise", and "Il Canto degli Italiani".
 It was the first collaboration between the composer and Arrigo Boito, who, much later, would revise the libretto of "Simon Boccanegra" and write the original libretti of "Otello" and "Falstaff".
Iva Pacetti (13 December 1898, Prato - 19 January 1981, Milan) was an Italian operatic soprano who had an active international career from 1920-1947.
 Trained in Florence and Milan, she made her professional opera debut in her native city at the age of 21 as the title heroine in Giuseppe Verdi's "Aida" at the Teatro Metastasio.
 She reprised the role the following year at Loew's Lexington Theatre in New York City.
 In 1922 she had a triumphant success at the Teatro Carlo Felice as Elena in Arrigo Boito's "Mefistofele".
 Engagements with other important opera houses soon followed, including La Scala, the Teatro Costanzi, the Teatro di San Carlo, the Opéra de Monte-Carlo, the Chicago Civic Opera, the Teatro Colón, the Teatro Municipal in Rio de Janeiro, and the Theatro Municipal in São Paulo.
 From 1930-1933 she was committed to the Royal Opera House in London, portraying such roles as Desdemona in "Otello", Leonora in "La forza del destino", and the title role in "Tosca".
 The latter years of her career were spent performing primarily at La Scala where she was a frequent partner of Beniamino Gigli.
 She retired from the stage in 1947, after which she was active as a voice teacher in Milan.
Maria Tudor is an opera in four acts composed by Antônio Carlos Gomes to an Italian-language libretto by Emilio Praga (completed by Arrigo Boito).
 The libretto is based on Victor Hugo's 1833 play "Marie Tudor", which centers on the rise, fall and execution of Fabiano Fabiani, a fictional favourite of Mary I of England.
 The opera premiered on 27 March 1879 at La Scala, Milan with Anna D'Angeri in the title role and Francesco Tamagno as Fabiani.
 The opera was a failure at its premiere and withdrawn, a heavy blow to Gomes who was in serious financial and family difficulties at the time.
 He returned to his native Brazil the following year.
La Gioconda is an opera in four acts by Amilcare Ponchielli set to an Italian libretto by Arrigo Boito (as Tobia Gorrio), based on "Angelo, Tyrant of Padua", a play in prose by Victor Hugo, dating from 1835.
 (This is the same source as Gaetano Rossi had used for his libretto for Mercadante's "Il giuramento" in 1837).

Question: Was Arrigo Boito the librettist for both Mefistofele and L'Orfeo?
Answer: no