The drama is presented using the typical elements of theater such as scenery, costumes, and acting. However, the words of the opera, or libretto, are sung rather than spoken. The singers are accompanied by a musical ensemble ranging from a small instrumental ensemble to a full symphonic orchestra.
Traditional opera consists of two modes of singing: recitative, the dialogue and plot-driving passages often sung in a non-melodic style characteristic of opera, and aria, during which the movement of the plot often stops and the music and the singers focus on one topic using full voice. Short sung passages are also referred to as arioso. Each type of singing is accompanied by musical instruments.
Singers and the roles they play are classified according to their vocal ranges. A particular singer's classifications change drastically over his or her lifetime, rarely reaching vocal maturity until well past middle age. Male singers are classified as bass, bass-baritone, baritone, tenor and countertenor. Female singers are classified, as contralto, mezzo-soprano and soprano. Each of these classifications has subcategories, (German, fach), such as lyric soprano, coloratura, soubrette, spinto, and dramatic soprano, which associate the singer's voice with the roles most suitable to the vocal timbre and quality and its range, or tessitura..
Opera draws from many other art forms. Whether the words or the music are paramount has been the subject of debate since the 17th century. The visual arts, such as painting, are employed to create the visual spectacle on the stage, which is considered an important part of the performance. Finally, dancing is often part of an opera performance.
The word opera means simply "works" in Latin, the plural of opus suggesting that it combines the arts of solo and choral singing, declamation, dancing in a staged spectacle. The earliest work considered an opera in the sense the work is usually understood dates from around 1597. It is Dafne, (now lost) written by Jacopo Peri for an elite circle of literate Florentine humanists who gathered as the "Camerata". Significantly Dafne was an attempt to revive the classical Greek drama, part of the wider revival of antiquity characteristic of the Renaissance. A later work by Peri, Euridice, dating from 1600, is the first opera score to have survived to the present day. Spoken or declaimed dialogue accompanied by an orchestra, called recitative in opera, is the essential feature of melodrama, in its original sense. The most familiar example of such incidental music is Mendelssohn's music for A Midsummer Night's Dream. The pit orchestra that underscored the dramatic action in 19th century melodrama survives in film scores, and spectacular films incorporating serious music are the direct heirs of melodrama and in their "special effects" both the heirs and the competitors of grand opera.
Earlier 17th century elements that had not yet fused into a recognizable opera included the courtly pageants called masques. New elements of masque, with many songs, were features of Shakespeare's "The Tempest" (ca. 1611). Musico-dramatic elements can also be seen in 16th century suites of madrigalss that were strung together to suggest a dramatic narrative.
In earlier times, music had been part of medieval mystery plays. A surviving musical work which is known to be older than Dafne is Philotea, to a religious text, by a priest called Silberman. Additionally, the music of Hildegard of Bingen has been given dramatic staged performances.
The bel canto opera movement flourished in the early 19th century and is exemplified by the operas of Rossini, Bellini, and Donizetti. 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.
Following the bel canto era, a more direct, forceful style was rapidly popularized by Giuseppe Verdi, beginning with his biblical opera Nabucco. Verdi's writing demanded vocal endurance and strength more than the agility required in bel canto; his works were also more demanding dramatically. Verdi's operas resonated with the growing spirit of Italian nationalism in the post-Napoleonic era, and he quickly became an icon of the nationalist movement (although his own politics were perhaps not quite so radical).
In rivalry with imported Italian opera productions, a separate French tradition, sung in the French, was founded by Italian Jean-Baptiste Lully, who established an Academy of Music and monopolized French opera from 1672. Lully's overtures, fluid and disciplined recitatives, danced interludes, divertissements and orchestral entr'actes between scenes, set a pattern that Gluck struggled to reform almost a century later. The text was as important as the music: royal propaganda was expressed in elaborate allegories, generally with upbeat endings. Opera in France has continued to include ballet interludes and feature elaborate scenic machinery.
Baroque French opera, elaborated by Rameau, was simplified by the reforms associated with Gluck (Alceste and Orfee) in the late 1760s. French opera was influenced by the bel canto of Rossini and other Italians (though sung in French).
Wagner pioneered a through-composed style, in which recitative and aria blend into one another and are constantly accompanied by the orchestra. Wagner also made copious use of the leitmotif (Weber had used a similar device earlier), a musical device which associates a musical line with each character or idea in the story.
Spain also produced its own distinctive form of opera, known as zarzuela, which had two separate flowerings: one in the 17th century, and another beginning in the mid-19th century. During the 18th century, Italian opera was immensely popular in Spain, supplanting the native form.