Question: Were the operas Alcina and Giulio Cesare both written by George Frideric Handel?

Context articles: Cecilia Young
Nicola Francesco Haym
Terpsicore
Orlando (opera)
Va tacito e nascosto
Alcina
Giulio Cesare la Galla
Giulio Cesare
List of operas by Handel
Svegliatevi nel core

Cecilia Young (also Cecilia Arne) (January 1712 – 6 October 1789) was one of the greatest English sopranos of the eighteenth century, the wife of composer Thomas Arne, and the mother of composer Michael Arne.
 According to music historian Charles Burney, she had "a good natural voice and a fine shake [and] had been so well taught, that her style of singing was infinitely superior to that of any other English woman of her time".
 She was part of a well-known English family of musicians that included several professional singers and organists.
 Young enjoyed a large amount of success through her close association with George Frideric Handel.
 She appeared in several of his oratorios and operas including the premieres of "Ariodante" (1735), "Alcina" (1735), "Alexander's Feast" (1736) and "Saul" (1739).
Nicola Francesco Haym (6 July 1678 – 31 July 1729) was an Italian opera librettist, composer, theatre manager and performer, and numismatist.
 He is best remembered for adapting texts into libretti for the London operas of George Frideric Handel and Giovanni Bononcini.
 Libretti that he provided for Handel included those for "Giulio Cesare", "Ottone", "Flavio", "Tamerlano", "Rodelinda", and several others; for Bononcini, he produced two, "Calfurnia" and "Astianatte".
Terpsicore (HWV)(8b) is a prologue in the form of an opéra-ballet by George Frideric Handel.
 Handel composed it in 1734 for a revision of his opera "Il pastor fido" which had first been presented in 1712.
 The revision of "Il pastor fido" with "Terpsicore" as the prologue was first performed on 9 November 1734 at Covent Garden theatre in London, opening Handel's first season in that newly built theatre.
 "Terpsicore" mixes dance along with solo and choral singing and was patterned after models in French operas, a particular source being "Les festes grecques et romaines" by Louis Fuzelier and Colin de Blamont, first presented in Paris in 1723.
 The work featured the celebrated French dancer Marie Sallé as well as stars of Handel's Italian operas and was a success with audiences of the day.
Orlando (HWV 31) is an opera seria in three acts by George Frideric Handel written for the King's Theatre in London in 1733.
 The Italian-language libretto was adapted from Carlo Sigismondo Capece's "L'Orlando" after Ludovico Ariosto's "Orlando Furioso", which was also the source of Handel's operas "Alcina" and "Ariodante".
 More an artistic than a popular success at its first performances, "Orlando" is today recognised as a masterpiece.
"Va tacito e nascosto" (Italian; translation, "Silently and stealthily") is an aria written for alto castrato voice in act 1 of George Frideric Handel's opera "Giulio Cesare in Egitto", composed in 1724 to a libretto by Nicola Francesco Haym.
 Sung by the character Julius Caesar, it features extensive solos for natural horn.
Alcina (HWV 34) is an opera seria by George Frideric Handel.
 Handel used the libretto of "L'isola di Alcina", an opera that was set in 1728 in Rome by Riccardo Broschi, which he acquired the year after during his travels in Italy.
 Partly altered for better conformity, the story was originally taken from Ludovico Ariosto's "Orlando furioso" (like those of the Handel operas "Orlando" and "Ariodante"), an epic poem.
 The opera contains several musical sequences with opportunity for dance: these were composed for dancer Marie Sallé.
Giulio Cesare la Galla (or Julius Cæsar Lagalla or Giulio Cesare Lagalla) (1576–1624) was a professor of philosophy at the Collegio Romano in Italy.
Giulio Cesare in Egitto (] ; Italian for "Julius Caesar in Egypt", HWV 17), commonly known as Giulio Cesare, is a dramma per musica ("opera seria") in three acts composed for the Royal Academy of Music by George Frideric Handel in 1724.
 The libretto was written by Nicola Francesco Haym who used an earlier libretto by Giacomo Francesco Bussani, which had been set to music by Antonio Sartorio (1676).
 The opera was a success at its first performances, was frequently revived by Handel in his subsequent opera seasons and is now one of the most often performed Baroque operas.
George Frideric Handel's operas comprise 42 musical dramas that were written between 1705 and 1741 in various genres.
 He began composing operas in Germany and then for a brief time in Italy to modest success.
 It was not until he moved to England that he found great success in the genre.
 His first opera in England, "Rinaldo" (1711), was met with enthusiasm, and several more Italian operas soon followed.
 However, Handel's place as the central figure of opera in England during the eighteenth century was not solidified until, under the influence of Thomas Arne, he began composing large-scale works with English language texts.
 Though almost all his English language works are technically oratorios and not operas, several of them, such as "Semele" (1743), have become an important part of the opera repertoire.
 Handel's first opera (opera seria - serious Italian opera) was "Almira" (1705).
"Svegliatevi nel core" is an aria taken from Act I, Scene IV of the Italian language opera seria, "Giulio Cesare", by George Frideric Handel.
 The aria is written for the role of “Sesto”, a soprano in trouser role, including during the premiere, who sings it to assure his mother that he will avenge the death of his father, Pompey, who was assassinated by the Egyptians, instructed by Tolomeo (Ptolemy XIII Theos Philopator) to demonstrate the Egyptians' loyalty to Julius Caesar.
 The words were written by Nicola Francesco Haym.