Il teatro alla moda (The Fashionable Theater) is a satirical pamphlet in which its author, the Venetian composer Benedetto Marcello (1686–1739), vents his critical opinions on the "milieu" of the Italian "opera seria" in the first decades of the eighteenth century.
 It was first published anonymously in Venice, by the end of 1720.
 Virtually every aspect of "opera seria" and its social environment is mercilessly criticized by Marcello: the artificiality of plots, the stereotyped format of music, the extravagant scenography and machinery, the inability and venality of composers and poets, the vanity and vulgarity of singers, the avidity of impresarios, the ineptitude of musicians.
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).
A number opera (Italian: "opera a numeri" ; German: "Nummeroper" ) is an opera consisting of individual pieces of music ('numbers') which can be easily extracted from the larger work.
 They may be numbered consecutively in the score, and may be interspersed with recitative or spoken dialogue.
 Opera numbers may be arias, but also ensemble pieces, such as duets, trios, quartets, quintets, sextets or choruses.
 They may also be ballets and instrumental pieces, such as marches, sinfonias, or intermezzi.
 The number opera format was standard until the mid-19th century and most opera genres, including "opera seria", "opera buffa", "opéra comique", ballad opera, Singspiel, and grand opera, were constructed in this fashion.
Flavio, re de' Longobardi ("Flavio, King of the Lombards", HWV 16) is an opera seria in three acts by George Frideric Handel.
 The Italian-language libretto was by Nicola Francesco Haym, after Matteo Noris's "Flavio Cuniberto".
 It was Handel's fourth full-length opera for the Royal Academy of Music.
 Handel had originally entitled the opera after the character of Emilia in the opera.
La Nitteti is an 18th-century Italian opera in 3 acts by the Czech composer Josef Mysliveček.
 It was composed to a libretto by the Italian poet Metastasio that was first performed in 1756, one of the newer (and less popular) of the Metastasian librettos in Mysliveček's day.
 For a performance in the 1770s, it would only be expected that a libretto of such age would be abbreviated and altered to suit contemporary operatic taste.
 This opera contains more substitutions of original aria texts than any other Mysliveček setting of a Metastasian libretto.
 The cuts and changes in the text made for the 1770 performance of Mysliveček's opera are not attributable.
 All of Mysliveček's operas are of the serious type in Italian language referred to as opera seria.
This is an inclusive list of opera festivals and summer opera seasons, and music festivals which have opera productions.
 This list may have some overlap with list of early music festivals.
 Opera is part of the Western classical music tradition, and has long been performed for audiences on a large-scale format.
 It started in Italy at the end of the 16th century and soon spread through the rest of Europe.
 In the 18th century, Italian opera continued to dominate most of Europe (except France), attracting foreign composers such as Handel.
 Opera seria was the most prestigious form of Italian opera, until Gluck reacted against its artificiality with his "reform" operas in the 1760s.
 Today the most renowned figure of late 18th century opera is Mozart, and his music is at times the featured attraction of opera and early music festivals.
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La Calliroe is an opera in three acts by Josef Mysliveček set to a libretto by Matteo Verazi that is based on Greek legends about the Oceanid Callirrhoe.
 This opera (and all the rest of Mysliveček's operas) belong to the serious type in Italian language referred to as "opera seria".
 Vocal pieces from the opera composed for the singer Luigi Marchesi in the role of Tarsile were widely copied in eighteenth-century collections of operatic arias.
Opera seria (] ; plural: "opere serie"; usually called "dramma per musica" or "melodramma serio") is an Italian musical term which refers to the noble and "serious" style of Italian opera that predominated in Europe from the 1710s to c. 1770.
 The term itself was rarely used at the time and only attained common usage once "opera seria" was becoming unfashionable and beginning to be viewed as a historical genre.
 The popular rival to "opera seria" was "opera buffa," the 'comic' opera that took its cue from the improvisatory commedia dell'arte.
Ezio ("Aetius", HWV 29) is an opera seria by George Frideric Handel to a libretto by Metastasio.
 Metastasio's libretto was partly inspired by Jean Racine's play "Britannicus".
 The same libretto had already been set by many other composers first of all Nicola Porpora who managed to preempt the official Rome premiere of Pietro Auletta's setting for 26 December 1728 with his own version (of a slightly edited copy of the libretto) for Venice on 20 November, a month earlier.
 The libretto continued to be set and reset for another 50 years, including two versions of "Ezio" by Gluck.
 Handel's "Ezio" is considered one of the purest examples of opera seria with its absence of vocal ensembles.
Tosca (] ) is an opera in three acts by Giacomo Puccini to an Italian libretto by Luigi Illica and Giuseppe Giacosa.
 It premiered at the Teatro Costanzi in Rome on 14 January 1900.
 The work, based on Victorien Sardou's 1887 French-language dramatic play, "La Tosca", is a melodramatic piece set in Rome in June 1800, with the Kingdom of Naples's control of Rome threatened by Napoleon's invasion of Italy.
 It contains depictions of torture, murder and suicide, as well as some of Puccini's best-known lyrical arias.

Question: Tosca is an Opera seria by who?
Answer: Giacomo Puccini to an Italian libretto by Luigi Illica and Giuseppe Giacosa