Italian opera
Opera did not remain confined to court audiences for long. In 1637, the idea of a "season" (often during the carnival) of publicly attended operas supported by ticket sales emerged in Venice. Monteverdi had moved to the city from Mantua and composed his last operas, Il ritorno d'Ulisse in patria and L'incoronazione di Poppea, for the Venetian theatre in the 1640s. His most important follower Francesco Cavalli helped spread opera throughout Italy. In these early Baroque operas, broad comedy was blended with tragic elements in a mix that jarred some educated sensibilities, sparking the first of opera's many reform movements, sponsored by the Arcadian Academy, which came to be associated with the poet Metastasio, whose libretti helped crystallise the genre of opera seria, which became the leading form of Italian opera until the end of the 18th century. Once the Metastasian ideal had been firmly established, comedy in Baroque-era opera was reserved for what came to be called opera buffa. Before such elements were forced out of opera seria, many libretti had featured a separately unfolding comic plot as sort of an "opera-within-an-opera". One reason for this was an attempt to attract members of the growing merchant class, newly wealthy, but still not as cultured as the nobility, to the public opera houses. These separate plots were almost immediately resurrected in a separately developing tradition that partly derived from the commedia dell'arte, a long-flourishing improvisatory stage tradition of Italy. Just as intermedi had once been performed in between the acts of stage plays, operas in the new comic genre of intermezzi, which developed largely in Naples in the 1710s and 1720s, were initially staged during the intermissions of opera seria. They became so popular, however, that they were soon being offered as separate productions.
Opera seria was elevated in tone and highly stylised in form, usually consisting of secco recitative interspersed with long da capo arias. These afforded great opportunity for virtuosic singing and during the golden age of opera seria the singer really became the star. The role of the hero was usually written for the high-pitched male castrato voice, which was produced by castration of the singer before puberty, which prevented a boy's larynx from being transformed at puberty. Castrati such as Farinelli and Senesino, as well as female sopranos such as Faustina Bordoni, became in great demand throughout Europe as opera seria ruled the stage in every country except France. Farinelli was one of the most famous singers of the 18th century. Italian opera set the Baroque standard. Italian libretti were the norm, even when a German composer like Handel found himself composing the likes of Rinaldo and Giulio Cesare for London audiences. Italian libretti remained dominant in the classical period as well, for example in the operas of Mozart, who wrote in Vienna near the century's close. Leading Italian-born composers of opera seria include Alessandro Scarlatti, Antonio Vivaldi and Nicola Porpora.
Opera seria had its weaknesses and critics. The taste for embellishment on behalf of the superbly trained singers, and the use of spectacle as a replacement for dramatic purity and unity drew attacks. Francesco Algarotti's Essay on the Opera (1755) proved to be an inspiration for Christoph Willibald Gluck's reforms. He advocated that opera seria had to return to basics and that all the various elements—music (both instrumental and vocal), ballet, and staging—must be subservient to the overriding drama. In 1765 Melchior Grimm published "Poème lyrique", an influential article for the Encyclopédie on lyric and opera librettos. Several composers of the period, including Niccolò Jommelli and Tommaso Traetta, attempted to put these ideals into practice. The first to succeed however, was Gluck. Gluck strove to achieve a "beautiful simplicity". This is evident in his first reform opera, Orfeo ed Euridice, where his non-virtuosic vocal melodies are supported by simple harmonies and a richer orchestra presence throughout.
Gluck's reforms have had resonance throughout operatic history. Weber, Mozart, and Wagner, in particular, were influenced by his ideals. Mozart, in many ways Gluck's successor, combined a superb sense of drama, harmony, melody, and counterpoint to write a series of comic operas with libretti by Lorenzo Da Ponte, notably Le nozze di Figaro, Don Giovanni, and Così fan tutte, which remain among the most-loved, popular and well-known operas. But Mozart's contribution to opera seria was more mixed; by his time it was dying away, and in spite of such fine works as Idomeneo and La clemenza di Tito, he would not succeed in bringing the art form back to life again.
The bel canto opera movement flourished in the early 19th century and is exemplified by the operas of Rossini, Bellini, Donizetti, Pacini, Mercadante and many others. Literally "beautiful singing", bel canto opera derives from the Italian stylistic singing school of the same name. Bel canto lines are typically florid and intricate, requiring supreme agility and pitch control. Examples of famous operas in the bel canto style include Rossini's Il barbiere di Siviglia and La Cenerentola, as well as Bellini's Norma, La sonnambula and I puritani and Donizetti's Lucia di Lammermoor, L'elisir d'amore and Don Pasquale.
Following the bel canto era, a more direct, forceful style was rapidly popularised by Giuseppe Verdi, beginning with his biblical opera Nabucco. This opera, and the ones that would follow in Verdi's career, revolutionised Italian opera, changing it from merely a display of vocal fireworks, with Rossini's and Donizetti's works, to dramatic story-telling. Verdi's operas resonated with the growing spirit of Italian nationalism in the post-Napoleonic era, and he quickly became an icon of the patriotic movement for a unified Italy. In the early 1850s, Verdi produced his three most popular operas: Rigoletto, Il trovatore and La traviata. The first of these, Rigoletto, proved the most daring and revolutionary. In it, Verdi blurs the distinction between the aria and recitative as it never before was, leading the opera to be "an unending string of duets". La traviata was also novel. It tells the story of courtesan, and it includes elements of verismo or "realistic" opera, because rather than featuring great kings and figures from literature, it focuses on the tragedies of ordinary life and society. After these, he continued to develop his style, composing perhaps the greatest French grand opera, Don Carlos, and ending his career with two Shakespeare-inspired works, Otello and Falstaff, which reveal how far Italian opera had grown in sophistication since the early 19th century. These final two works showed Verdi at his most masterfully orchestrated, and are both incredibly influential, and modern. In Falstaff, Verdi sets the pre-eminent standard for the form and style that would dominate opera throughout the twentieth century. Rather than long, suspended melodies, Falstaff contains many little motifs and mottos, that, rather than being expanded upon, are introduced and subsequently dropped, only to be brought up again later. These motifs never are expanded upon, and just as the audience expects a character to launch into a long melody, a new character speaks, introducing a new phrase. This fashion of opera directed opera from Verdi, onward, exercising tremendous influence on his successors Giacomo Puccini, Richard Strauss, and Benjamin Britten.
After Verdi, the sentimental "realistic" melodrama of verismo appeared in Italy. This was a style introduced by Pietro Mascagni's Cavalleria rusticana and Ruggero Leoncavallo's Pagliacci that came to dominate the world's opera stages with such popular works as Giacomo Puccini's La bohème, Tosca, and Madama Butterfly. Later Italian composers, such as Berio and Nono, have experimented with modernism.