Question: What nationality/style of Opera did both Alessandro Scarlatti and Christoph Willibald Gluck compose?

Context articles: Baldassare Galuppi
Giuseppe Scarlatti
Paride ed Elena
Orfeo ed Euridice discography
Gluck (crater)
Armida (Salieri)
Alessandro Scarlatti
Orfeo ed Euridice
Ipermestra
Christoph Willibald Gluck

Baldassare Galuppi (18 October 17063 January 1785) was an Italian composer, born on the island of Burano in the Venetian Republic.
 He belonged to a generation of composers, including Christoph Willibald Gluck, Domenico Scarlatti, and C. P. E. Bach, whose works are emblematic of the prevailing galant style that developed in Europe throughout the 18th century.
 He achieved international success, spending periods of his career in Vienna, London and Saint Petersburg, but his main base remained Venice, where he held a succession of leading appointments.
Giuseppe Scarlatti (1718 or 18 June 1723, Naples – 17 August 1777, Vienna) was a composer of "opere serie" and "opere buffe".
 He worked in Rome from 1739 to 1741, and from 1752 to 1754 in Florence, Pisa, Lucca and Turin.
 From 1752 to 1754, and again from 1756 to 1759, he worked in Venice and for short periods in Milan and Barcelona.
 In 1760 he moved to Vienna, where he enjoyed the friendship of Christoph Willibald Gluck.
 "The third most important musician of his clan", it is still uncertain whether he was the nephew of Alessandro born 18 June 1723 or the nephew of Domenico born in 1718.
 Giuseppe Scarlatti was married to the Viennese singer Barbara Stabili who died about 1753.
 By 1767 he had married Antonia Lefebvre, who that year bore him a son; she died three years later.
 Scarlatti died intestate in 1777 in Vienna.
Paride ed Elena (] ; "Paris and Helen") is an opera by Christoph Willibald Gluck.
 It is the third of Gluck's so-called reform operas for Vienna, following "Alceste" and "Orfeo ed Euridice", and the least often performed of the three.
 Like its predecessors, the libretto was written by Ranieri de' Calzabigi.
 The opera tells the story of the events between the Judgment of Paris and the flight of Paris and Helen to Troy.
 It was premiered at the Burgtheater in Vienna on 3 November 1770.
The following discography for Gluck's opera "Orfeo ed Euridice" is mainly based on the research of Giuseppe Rossi, which appeared in the programme notes to the performance of the work at the 70th Maggio Musicale Fiorentino in 2007, under the title "Discografia – Christoph Willibald Gluck – Orfeo ed Euridice (Orphée et Eurydice)".
 Rossi's data has been checked against the sources referenced in the notes.
Gluck is a crater on Mercury.
 It has a diameter of 105 kilometers.
 Its name was adopted by the International Astronomical Union in 1979.
 Gluck is named for the Austrian composer Christoph Willibald Gluck, who lived from 1714 to 1787.
Salieri's opera was first performed at the Vienna Burgtheater on 2 June 1771, and his composition was much influenced by the aesthetics of Christoph Willibald Gluck, who attempted to reform "opera seria" by tying the drama more closely to the music.
 Salieri's overture follows the principles set out by Gluck in the preface to "Alceste".
 Other Gluckian influences display themselves in the frequent interplay of soloist and chorus, and the heavy use of chorus overall.
Pietro Alessandro Gaspare Scarlatti (2 May 1660 – 22 October 1725) was an Italian Baroque composer, especially famous for his operas and chamber cantatas.
 He is considered the founder of the Neapolitan school of opera.
 He was the father of two other composers, Domenico Scarlatti and Pietro Filippo Scarlatti.
Orfeo ed Euridice (French version: Orphée et Eurydice ; English: "Orpheus and Eurydice") is an opera composed by Christoph Willibald Gluck based on the myth of Orpheus, set to a libretto by Ranieri de' Calzabigi.
 It belongs to the genre of the "azione teatrale", meaning an opera on a mythological subject with choruses and dancing.
 The piece was first performed at the Burgtheater in Vienna on 5 October 1762 in the presence of Empress Maria Theresa.
 "Orfeo ed Euridice" is the first of Gluck's "reform" operas, in which he attempted to replace the abstruse plots and overly complex music of "opera seria" with a "noble simplicity" in both the music and the drama.
Ipermestra ("Hypermnestra") is an opera by the composer Christoph Willibald Gluck.
 It takes the form of an opera seria in three acts.
 The Italian-language libretto is by Pietro Metastasio.
 The opera premiered on 21 November 1744 at the Teatro San Giovanni Grisostomo in Venice.
 "Ipermestra" is the first of Gluck's operas to survive complete.
Christoph Willibald (Ritter von) Gluck (] ; 2 July 1714 – 15 November 1787) was a composer of Italian and French opera in the early classical period.
 Born in the Upper Palatinate (now part of Germany) and raised in Bohemia, he gained prominence at the Habsburg court at Vienna, where he brought about the practical reform of opera's dramaturgical practices that many intellectuals had been campaigning for over the years.
 With a series of radical new works in the 1760s, among them "Orfeo ed Euridice" and "Alceste", he broke the stranglehold that Metastasian "opera seria" had enjoyed for much of the century.