Fidelio (Op. 72) is a German opera in two acts by Ludwig van Beethoven. It is Beethoven's only opera. The German libretto is by Joseph Sonnleithner from the French of Jean-Nicolas Bouilly which had been used for the 1798 opera Léonore, ou L’amour conjugal by Pierre Gaveaux, and for the 1804 opera Leonora by Ferdinando Paer (a score of which was owned by Beethoven). The opera tells how Leonore, disguised as a prison guard named "Fidelio", rescues her husband Florestan from death in a political prison.

Bouilly's scenario fits Beethoven's aesthetic and political outlook: a story of personal sacrifice, heroism and eventual triumph (the usual topics of Beethoven's "middle period") with its underlying struggle for liberty and justice mirroring contemporary political movements in Europe.

As elsewhere in Beethoven's vocal music, the music is not especially kind to the singers. The principal parts of Leonore and Florestan, in particular, require great vocal skill and endurance in order to project the necessary intensity, and top performances in these roles attract admiration.

Ludwig van Beethoven (ⁱ/ˈlʊdvɪɡ væn ˈbeɪt.hoʊvən/; German pronunciation: [ˈluːtvɪç fan ˈbeːt.hoːfən] ( listen); baptized 17 December 1770 – 26 March 1827) was a German composer and pianist. A crucial figure in the transition between the Classical and Romantic eras in Western art music, he remains one of the most famous and influential of all composers.

Born in Bonn, then the capital of the Electorate of Cologne and part of the Holy Roman Empire, Beethoven moved to Vienna in his early 20s, studying with Joseph Haydn and quickly gaining a reputation as a virtuoso pianist. His hearing began to deteriorate in his late twenties, yet he continued to compose, conduct, and perform, even after becoming completely deaf.

Beethoven was the grandson of a musician of Flemish origin named Lodewijk van Beethoven (1712–73) who moved at the age of twenty to Bonn. Lodewijk (Ludwig is the German cognate of Dutch Lodewijk) was employed as a bass singer at the court of the Elector of Cologne, eventually rising to become Kapellmeister (music director). Lodewijk had one son, Johann (1740–1792), who worked as a tenor in the same musical establishment, and gave lessons on piano and violin to supplement his income. Johann married Maria Magdalena Keverich in 1767; she was the daughter of Johann Heinrich Keverich, who had been the head chef at the court of the Archbishopric of Trier.

Leonard Bernstein ( /ˈbɜrnstaɪn/ US dict: bûrn′·stīn; August 25, 1918 – October 14, 1990) was an American composer, conductor, author, music lecturer and pianist. He was among the first conductors born and educated in the United States of America to receive worldwide acclaim. According to The New York Times, he was "one of the most prodigiously talented and successful musicians in American history."

His fame derived from his long tenure as the music director of the New York Philharmonic, from his conducting of concerts with most of the world's leading orchestras, and from his music for West Side Story, as well as Candide, Wonderful Town, On the Town and his own Mass.

Bernstein was also the first conductor to give numerous television lectures on classical music, starting in 1954 and continuing until his death. In addition, he was a skilled pianist, often conducting piano concertos from the keyboard.

As a composer he wrote in many styles encompassing symphonic and orchestral music, ballet, film and theatre music, choral works, opera, chamber music and pieces for the piano. Many of his works are regularly performed around the world, although none has matched the tremendous popular and commercial success of West Side Story.

Christa Ludwig (born 16 March 1928) is a retired German mezzo-soprano, distinguished for her performances of opera, Lieder, oratorio and other major religious works like masses and passions, and solos contained in symphonic literature. Her career spanned from the late 1940s until the early 1990s.

Ludwig was born in Berlin to a musical family; her father, Anton Ludwig, was a tenor and an operatic administrator, her mother, the mezzo-soprano Eugenie Besalla-Ludwig who sang at the Aachen Opera during Herbert von Karajan's period as conductor. Ludwig's first voice teacher was her mother.

Ludwig made her debut in 1946 at the age of 18 as Orlovsky in Die Fledermaus at Frankfurt, where she sang until 1952. She was a member of the Darmstadt Opera from 1952 to 1954, then sang the 1954–1955 season at the Staatsoper Hannover. She joined the Vienna State Opera in 1955, where she became one of its principal artists and was appointed Kammersängerin in 1962 and performed with the company for more than thirty years. In 1954, Ludwig made her debut at the Salzburg Festival as Cherubino in Le nozze di Figaro, and appeared there regularly until 1981. Ludwig made her debut as Brangäne in Tristan und Isolde at the Bayreuth Festival in 1966. In 1960, she performed as Adalgisa alongside Maria Callas as Norma, in Bellini's opera by the same title.

Jonas Kaufmann (born 10 July 1969) is a German operatic tenor. Although he has sung a variety of leading roles including both the Mozart and Wagner repertoire, he is particularly known for his performances in spinto roles such as Don José in Carmen, Cavaradossi in Tosca, Maurizio in Adriana Lecouvreur, and the title role in Don Carlos.

Kaufmann was born in Munich. His father worked for an insurance company, and his mother was a kindergarten teacher. He had one older sister. He started studying piano when he was eight, and he sang in his elementary school choir. Although he studied for math entrance exams, in the summer of 1989 he began his vocal training at the University of Music and Performing Arts Munich. While studying, he sang some small roles at the Bavarian State Opera. He graduated from school in 1994.

In 1995, after a vocal crisis, Kaufmann received help from American baritone Michael Rhodes who taught him a "new way of singing" and how to become "more relaxed in my voice and in myself." In Kaufmann's book Meinen die wirklich mich? he said, "To find a Michael Rhodes that can really help you and bring you to success is really a great stroke of luck."