Of all Latin American composers, the most widely performed today in classical circles is surely Astor Piazzolla, who has achieved something resembling pop status within the past three decades. Born in Argentina, he grew up in New York City, where his family moved in 1925; there he learned to play the bandoneon, a concertina accordion whose timbre instantly evokes the Argentine tango. 

Returning to his native country at the age of 16, he established himself as a working musician and performed with many popular ensembles before forming his own tango orchestra, the Orquesta del 46, in 1946, the year he wrote his first tango.  In 1950 he disbanded his ensemble, the better to dedicate his time to composing, and as early as 1953 he produced his first works for symphonic forces. The following year he received a grant from the French Government to travel to Paris; there he studied with Nadia Boulanger, who urged him to develop his language as a composer on a foundation of distinctly Argentine sound. He recalled:

Up to then I had composed symphonies, chamber music, string quartets; but when Nadia Boulanger analyzed my music, she said she could find nowhere any Piazzolla. She could find Ravel and Stravinsky, also Bartók and Hindemith — but never Piazzolla. … Nadia made me play a tango to her and then she said, “You idiot! That is the real Piazzolla!” So, I threw away all the other music and, in 1954, started working on my New Tango.

By 1956 he began presenting these new, hybrid tangos in concert. On his return to Argentina he formed another ensemble, the Octeto de Buenos Aires, the first of several chamber groups that would serve as a sort of laboratory for his continuing experiments in developing tango as a genre of contemporary music. The tango he inherited was an overtly sexy dance born in the back alleys and brothels of Buenos Aires. Piazzolla injected a sense of modernity into the genre, so transforming it that his music, and that of his colleagues and followers, defines ‘the new tango’ (Tango Nuevo) in contrast with the classic dance form, which is referred to as ‘tango de la guardia vieja’ (tango of the old guard). While the classic tango remains recognizable as the root of his music his pieces also reflect aspects of jazz and of classical developments that trace their ancestry to Stravinsky.

Piazzolla’s works met resistance from tango traditionalists, many of whom dismissed them outright. Indeed, he viewed his compositions as essentially works of classical chamber music. The eclecticism of his source material, once a stumbling block to his critics, is now a major source of appeal for today's increasingly diverse audiences. Piazzolla's music has been especially embraced in the classical music community, where it has found such distinguished champions as Yo-Yo Ma, Gidon Kremer, and the Kronos Quartet. A growing number of arrangements of his works are being produced for ensembles of various sizes and configurations, so that more musicians can have the pleasure of bringing Piazzolla's music to an ever-wider public. 

Concierto para Quinteto was premiered in 1971 and was designed to feature the musicians of the Quinteto Nuevo Tango, the most successful of Piazzolla's groundbreaking ensembles: it is scored for bandoneon, violin, electric guitar, piano, and double bass. It consists of three sections, and at nine minutes in length it is among his more substantial instrumental pieces. It exhibits all the traits of his mature compositional style, it remained in his active performance repertory until the end of his career.

Trilogie de L’Angle (The Angel Trilogy) was composed for the Quinteto Nuevo Tango, directed by Piazzolla himself. The composition began in 1962 and was finished in 1965 for Alberto Rodriguez Muñoz’s 1962 stage play Tango del Angel. In the play, the music accompanies "the story of an angel who tries to heal the broken spirits of humans in a house in Buenos Aires, only to die in a knife fight."

Piazzolla added two new pieces to an earlier tango that gave the play its name. This music reappeared in at least two different concert forms, but one of the unifying elements is Milonga del Ángel. A milonga is a sort of proto-tango, lighter and gentler than the more familiar form. This milonga is openly sentimental and begins with a lounge music feel with strummed bass chords; a simple, lamenting violin line; and a few tinkles from the piano. The bandoneon creeps in almost unnoticed, but takes control of the piece with a sad, nostalgic melody. 

La Muerte del Angel (Death of the Angel) is composed as a fugue in four voices. Fugue is one of the formal classical styles Piazzolla used to particularly dramatic effect. The word “Fugue” means “to chase” and that is almost literally the implication of the way in which the entries of the main fugue theme “chase” one another. With Piazzolla’s trademark rhythmic drive – bordering on obsessive compulsive – his fugues are particularly exciting. In a 1989 interview Piazzolla said: “…but my main style is to have studied. If I had not, I would not be doing what I do, what I’ve done. Because everybody thinks that to do a ‘modern tango’ is to make noise, is to make strange thoughts, and no, that’s not true! You have to go a little deeper, and you can see that what I do is very elaborate. If I do a fugue in the manner of Bach, it will always be “tangoficated”. 

Although Piazzolla purposely didn’t worry about accomplishing the academic and rigorous steps of a typical method, this piece nevertheless showcases the ease with which he manages the musical form. It is necessary to point out the natural conciliation that Piazzolla achieves between a tango and a musical form that is typically baroque. The Angel ‘suite’ is a classic example of Piazzolla’s ability to take advantage of the European traditions and submit them into the pulse of his own style.