Given the question: Information:  - An oratorio is a large musical composition for orchestra, choir, and soloists. Like an opera, an oratorio includes the use of a choir, soloists, an ensemble, various distinguishable characters, and arias. However, opera is musical theatre, while oratorio is strictly a concert piecethough oratorios are sometimes staged as operas, and operas are sometimes presented in concert form. In an oratorio there is generally little or no interaction between the characters, and no props or elaborate costumes. A particularly important difference is in the typical subject matter of the text. Opera tends to deal with history and mythology, including age-old devices of romance, deception, and murder, whereas the plot of an oratorio often deals with sacred topics, making it appropriate for performance in the church. Protestant composers took their stories from the Bible, while Catholic composers looked to the lives of saints, as well as to Biblical topics. Oratorios became extremely popular in early 17th-century Italy partly because of the success of opera and the Catholic Church's prohibition of spectacles during Lent. Oratorios became the main choice of music during that period for opera audiences.  - The masque was a form of festive courtly entertainment that flourished in 16th- and early 17th-century Europe, though it was developed earlier in Italy, in forms including the intermedio (a public version of the masque was the pageant). A masque involved music and dancing, singing and acting, within an elaborate stage design, in which the architectural framing and costumes might be designed by a renowned architect, to present a deferential allegory flattering to the patron. Professional actors and musicians were hired for the speaking and singing parts. Often the masquers, who did not speak or sing, were courtiers: the English queen Anne of Denmark frequently danced with her ladies in masques between 1603 and 1611, and Henry VIII and Charles I of England performed in the masques at their courts. In the tradition of masque, Louis XIV of France danced in ballets at Versailles with music by Jean-Baptiste Lully.  - A song, most broadly, is a single (and often standalone) work of music that is typically intended to be sung by the human voice with distinct and fixed pitches and patterns using sound and silence and a variety of forms that often include the repetition of sections. Written words created specifically for music or for which music is specifically created, are called lyrics. If a pre-existing poem is set to composed music in classical music it is an art song. Songs that are sung on repeated pitches without distinct contours and patterns that rise and fall are called chants. Songs in a simple style that are learned informally are often referred to as folk songs. Songs that are composed for professional singers who sell their recordings or live shows to the mass market are called popular songs. These songs, which have broad appeal, are often composed by professional songwriters, composers and lyricists. Art songs are composed by trained classical composers for concert or recital performances. Songs are performed live and recorded on audio or video (or in some, cases, a song may be performed live and simultaneously recorded). Songs may also appear in plays, musical theatre, stage shows of any form, and within operas.  - A Singspiel (plural: Singspiele; literally "sing-play") is a form of German-language music drama, now regarded as a genre of opera. It is characterized by spoken dialogue, which is alternated with ensembles, songs, ballads, and arias which were often strophic, or folk-like. Singspiel plots are generally comic or romantic in nature, and frequently include elements of magic, fantastical creatures, and comically exaggerated characterizations of good and evil. History. Some of the first Singspiele were miracle plays in Germany, where dialogue was interspersed with singing. By the early 17th century, miracle plays had grown profane, the word "Singspiel" is found in print, and secular Singspiele were also being performed, both in translated borrowings or imitations from English and Italian songs and plays, and in original German creations.  - A tradition is a belief or behavior passed down within a group or society with symbolic meaning or special significance with origins in the past. Common examples include holidays or impractical but socially meaningful clothes (like lawyers' wigs or military officers' spurs), but the idea has also been applied to social norms such as greetings. Traditions can persist and evolve for thousands of yearsthe word "tradition" itself derives from the Latin "tradere" or "traderer" literally meaning to transmit, to hand over, to give for safekeeping. While it is commonly assumed that traditions have ancient history, many traditions have been invented on purpose, whether that be political or cultural, over short periods of time. Various academic disciplines also use the word in a variety of ways.   - Ballet is a type of performance dance that originated in the Italian Renaissance courts of the 15th century and later developed into a concert dance form in France and Russia. It has since become a widespread, highly technical form of dance with its own vocabulary based on French terminology. It has been globally influential and has defined the foundational techniques used in many other dance genres. Becoming a ballet dancer requires years of training. Ballet has been taught in various schools around the world, which have historically incorporated their own cultures to evolve the art.  - Costume is the distinctive style of dress of an individual or group that reflects their class, gender, profession, ethnicity, nationality, activity or epoch.  - A Requiem or Requiem Mass, also known as Mass for the dead (Latin: "Missa pro defunctis") or Mass of the dead (Latin: "Missa defunctorum"), is a Mass in the Catholic Church offered for the repose of the soul or souls of one or more deceased persons, using a particular form of the Roman Missal. It is frequently, but not necessarily, celebrated in the context of a funeral.  - Operetta is a genre of light opera, "light" in terms both of music and subject matter.  - A pianist is an individual musician who plays the piano. Most forms of Western music can make use of the piano. Consequently, pianists have a wide variety of repertoire and styles to choose from, including traditionally classical music, Jazz, blues and all sorts of popular music, including rock music. Most pianists can, to a certain extent, play other keyboard-related instruments such as the synthesizer, harpsichord, celesta and the organ and keyboard. Perhaps the greatest pianist of all time was Franz Liszt, whose piano mastery was described by Anton Rubinstein: "In comparison with Liszt, all other pianists are children".   - Acting is an activity in which a story is told by means of its enactment by an actor or actress who adopts a characterin theatre, television, film, radio, or any other medium that makes use of the mimetic mode.  - Drama is the specific mode of fiction represented in performance. The term comes from a Greek word meaning "action" (Classical Greek: , "drama"), which is derived from "to do" (Classical Greek: , "drao").  The two masks associated with drama represent the traditional generic division between comedy and tragedy. They are symbols of the ancient Greek Muses, Thalia, and Melpomene. Thalia was the Muse of comedy (the laughing face), while Melpomene was the Muse of tragedy (the weeping face). Considered as a genre of poetry in general, the dramatic mode has been contrasted with the epic and the lyrical modes ever since Aristotle's "Poetics" (c. 335 BCE)the earliest work of dramatic theory.  - One Thousand and One Nights ("kitb alf layla wa-layla") is a collection of Middle Eastern and South Asian stories and folk tales compiled in Arabic during the Islamic Golden Age. It is often known in English as the Arabian Nights, from the first English language edition (1706), which rendered the title as "The Arabian Nights' Entertainment".  - Dance is a performance art form consisting of purposefully selected sequences of human movement. This movement has aesthetic and symbolic value, and is acknowledged as dance by performers and observers within a particular culture. Dance can be categorized and described by its choreography, by its repertoire of movements, or by its historical period or place of origin.  - A composer (Latin "compn"; literally "one who puts together") is a person who creates or writes music, which can be vocal music (for a singer or choir), instrumental music (e.g., for solo piano, string quartet, wind quintet or orchestra) or music which combines both instruments and voices (e.g., opera or art song, which is a singer accompanied by a pianist). The core meaning of the term refers to individuals who have contributed to the tradition of Western classical music through creation of works expressed in written musical notation (e.g., sheet music scores).  - Abu Hassan is a comic opera in one act by Carl Maria von Weber to a German libretto by Franz Carl Hiemer , based on a story in One Thousand and One Nights . It was composed between 11 August 1810 and 12 January 1811 and has set numbers with recitative and spoken dialogue . The work is a Singspiel in the then popular Turkish style .  - Dialogue (sometimes spelled dialog in U.S. English) is a written or spoken conversational exchange between two or more people, and a literary and theatrical form that depicts such an exchange. As a narrative, philosophical or didactic device, it is chiefly associated in the West with the Socratic dialogue as developed by Plato, but antecedents are also found in other traditions including Indian literature. In the 20th century, philosophical treatments of dialogue emerged from thinkers including Mikhail Bakhtin, Paulo Freire, Martin Buber, and David Bohm. Although diverging in many details, these thinkers have articulated a holistic concept of dialogue as a multi-dimensional, dynamic and context-dependent process of creating meaning. Educators such as Freire and Ramón Flecha have also developed a body of theory and technique for using egalitarian dialogue as a pedagogical tool.  - A libretto is the text used in, or intended for, an extended musical work such as an opera, operetta, masque, oratorio, cantata or musical. The term "libretto" is also sometimes used to refer to the text of major liturgical works, such as the Mass, requiem and sacred cantata, or the story line of a ballet.  - An aria (plural: "arie" , or "arias" in common usage, diminutive form arietta or ariette) in music was originally any expressive melody, usually, but not always, performed by a singer. The term became used almost exclusively to describe a self-contained piece for one voice, with or without orchestral accompaniment, normally part of a larger work. The typical context for arias is opera, but vocal arias also feature in oratorios and cantatas, sharing features of the operatic arias of their periods.  - Islam (' ;) is a religion articulated by the Quran, a text considered by its adherents to be the verbatim word of God ('), and, for the vast majority of adherents, the teachings and normative example (called the "sunnah", composed of accounts called "hadith") of Muhammad (5708 June 632 CE). It is the world's second-largest religion and the fastest-growing major religion in the world, with over 1.7 billion followers or 23% of the global population, known as Muslims. Islam is an Abrahamic monotheistic religion that upholds that God is one and incomparable and that the purpose of existence is to worship God. Muslims consider Muhammad to be the last prophet of God.  - An opera house is a theatre building used for opera performances that consists of a stage, an orchestra pit, audience seating, and backstage facilities for costumes and set building. While some venues are constructed specifically for operas, other opera houses are part of larger performing arts centers.  - A critic is a professional who communicates an assessment and an opinion of various forms of creative works such as art, literature, music, cinema, theater, fashion, architecture, and food. Critics may also take as their subject social or government policy. Critical judgments, whether derived from critical thinking or not, weigh up a range of factors, including an assessment of the extent to which the item under review achieves its purpose and its creator's intention and a knowledge of its context. They may also include a positive or negative personal response.  - A guitarist (or a guitar player) is a person who plays the guitar. Guitarists may play a variety of guitar family instruments such as classical guitars, acoustic guitars, electric guitars, and bass guitars. Some guitarists accompany themselves on the guitar by singing or playing the harmonica.  - A ballad is a form of verse, often a narrative set to music. Ballads derive from the medieval French "chanson balladée" or "ballade", which were originally "danced songs". Ballads were particularly characteristic of the popular poetry and song of the British Isles from the later medieval period until the 19th century. They were widely used across Europe, and later in the Americas, Australia and North Africa. Ballads are 13 lines with an ABABBCBC form, consisting of couplets (two lines) of rhymed verse, each of 14 syllables.  - The Middle East is a transcontinental region centered on Western Asia and Egypt. The corresponding adjective is "Middle-Eastern" and the derived noun is "Middle-Easterner". The term has come into wider usage as a replacement of the term Near East (as opposed to Far East) beginning in the early 20th century.  - An orchestra is a large instrumental ensemble typical of classical music, which features string instruments such as violin, viola, cello and double bass, as well as brass, woodwinds, and percussion instruments, grouped in sections. Other instruments such as the piano and celesta may sometimes appear in a fifth keyboard section or may stand alone, as may the concert harp and, for performances of some modern compositions, electronic instruments.  - Carl Maria Friedrich Ernst von Weber (18 or 19 November 1786 5 June 1826) was a German composer, conductor, pianist, guitarist and critic, one of the first significant composers of the Romantic school.  - Theatre or theater is a collaborative form of fine art that uses live performers, typically actors or actresses, to present the experience of a real or imagined event before a live audience in a specific place, often a stage. The performers may communicate this experience to the audience through combinations of gesture, speech, song, music, and dance. Elements of art, such as painted scenery and stagecraft such as lighting are used to enhance the physicality, presence and immediacy of the experience. The specific place of the performance is also named by the word "theatre" as derived from the Ancient Greek  (théatron, "a place for viewing"), itself from  (theáomai, "to see", "to watch", "to observe").  - A cantata (literally "sung", past participle feminine singular of the Italian verb "cantare", "to sing") is a vocal composition with an instrumental accompaniment, typically in several movements, often involving a choir.  - Recitative (also known by its Italian name "recitativo") is a style of delivery (much used in operas, oratorios, and cantatas) in which a singer is allowed to adopt the rhythms of ordinary speech. Recitative does not repeat lines as formally composed songs do. It resembles sung ordinary speech more than a formal musical composition.  - A musician (or instrumentalist) is a person who plays a musical instrument or is musically talented. Anyone who composes, conducts, or performs music may also be referred to as a musician.   - Opera (English plural: "operas"; Italian plural: "opere" ) is an art form in which singers and musicians perform a dramatic work combining text (libretto) and musical score, usually in a theatrical setting. In traditional opera, singers do two types of singing: recitative, a speech-inflected style and arias, a more melodic style. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble, which since the early 19th century has been led by a conductor.  - A musical ensemble, also known as a music group or musical group, is a group of people who perform instrumental and/or vocal music, with the ensemble typically known by a distinct name. Some music ensembles consist solely of instruments, such as the jazz quartet or the orchestra. Some music ensembles consist solely of singers, such as choirs and doo wop groups. In both popular music and classical music, there are ensembles in which both instrumentalists and singers perform, such as the rock band or the Baroque chamber group for basso continuo (harpsichord and cello) and one or more singers. In classical music, trios or quartets either blend the sounds of musical instrument families (such as piano, strings, and wind instruments) or group together instruments from the same instrument family, such as string ensembles (e.g., string quartet) or wind ensembles (e.g., wind quintet). Some ensembles blend the sounds of a variety of instrument families, such as the orchestra, which uses a string section, brass instruments, woodwinds and percussion instruments, or the concert band, which uses brass, woodwinds and percussion.     What entity does 'abu hassan' has the relation 'genre' with?
The answer is:
operetta