Frédéric Rzewski, a formidable composer and pianist who wrote and performed music that was both stylistically eclectic and politically engaged, died on Saturday at his summer residence in Montiano, Italy. He was 83 years old.

The cause was cardiac arrest, publicist Josephine Hemsing said in an email.

Mr. Rzewski’s anti-establishment thinking has been central to his musical creation throughout his life. It was evident in the experimentation, agitprop improvisations he premiered in the 1960s with the Musica Elettronica Viva ensemble; in “Come together,” the minimalist classic inspired by the Attica prison uprising; and an extensive catalog of works for solo piano, many of which have become cornerstones of the modern repertoire.

His approach was embodied in his most famous play, “The united people will never be defeated! “ an expansive and virtuoso ensemble of 36 variations on a Chilean protest song.

Composed for pianist Ursula Oppens in 1975, the hour-long piece is a torrent of inventive and unusual techniques – the pianist whistles, screams and slams the lid of the instrument – and has been compared to canonical works like the Beethoven’s “Diabelli Variations” and Bach’s “Goldberg Variations”.

“Stylistically, it goes through everything,” Ms. Oppens said in a recent interview. “It’s pointillist and minimalist and really quite varied.” At the same time, she noted, Mr. Rzewski’s mastery of traditional counterpoint was a major draw for pianists. “There is a logic in the relationship of the notes between them,” she added.

“The People United” has captured the imagination of virtuosos whose Marc-André Hamelin and, more recently, young pianists like Igor levit and Conrad Tao. This is what comes closest to a war horse in the contemporary pianistic repertoire.

In 2015, Mr. Rzewski carried out all the work at Pittsburgh Wholey’s Fish Market, a legendary event in contemporary music circles.

Mr. Rzewski’s musical approach favored intuition over cerebral composition. “The only thing 20th century composers don’t do is just write the tunes that come to mind,” he said. told NewMusicBox magazine in 2002. “I write just what I have in mind.”

Frederic Anthony Rzewski was born on April 13, 1938 in Westfield, Massachusetts, to Anthony Rzewski, a Polish emigrant, and Emma Buynicki, both pharmacists. He started playing the piano and composing from an early age.

Following the advice of a professor, he consults Shostakovich and Schoenberg albums in a record store and begins to immerse himself in musical modernism.

After graduating from Phillips Academy in Massachusetts, Mr. Rzewski studied music at Harvard with tonal composers Randall Thompson and Walter Piston. He received his masters degree from Princeton.

In 1960 and 1961, he studied with Luigi Dallapiccola in Florence thanks to a Fulbright scholarship. In Europe he gained fame performing the music of luminaries like Karlheinz Stockhausen and, after a stint in Berlin to study with Elliott Carter, settled in Rome.

The European avant-garde had fallen in the grip of the experimentalism of John Cage, and Mr. Rzewski wrote intoxicating music like his “Composition for Two Players”, an unconventional score which he once performed by placing sheets of glass on the strings of a Steinway.

In 1966, he and composer Alvin Curran assembled a group of musicians, including electronic composer Richard Teitelbaum, to perform in the crypt of a church in Rome. The collective became Musica Elettronica Viva, an act that used home electronics configurations for visceral improvisations. Mr. Rzewski, for example, strummed and drummed on a piece of glass that had been cut out in the shape of a piano, to which he had attached a microphone. (“By the grace of God, we were not electrocuted,” he later said.)

Rejecting the dense, modernist scores of his previous academic environment, Mr. Rzewski became preoccupied with spontaneity.

“The sublime mingled freely with the base”, he wrote one day about “Spatialship,” one of the trippy instruction sets that guided Musica Elettronica Viva’s performances. “Paroxysms of exhausting intensity alternated with Tibetan drones, ecstatic trances gave way to demonic crises in rapid succession.”

The collective gave over 100 performances across Europe in the late 1960s, and its loud concerts attracted increasingly politicized listeners. As the students fidgeted, the group joined in, inviting the audience to perform with them in anarchic improvisations – a sort of avant-garde Summer of Love. The group also performed in factories and prisons.

“The most important thing was the connection between the community and the political,” said composer and scholar George E. Lewis, who played in later versions of the collective, in a recent interview. “Music has given people choices and options, and the collective creation of music has allowed everyone to rethink their situation. “

In 1971, Mr. Rzewski moved to New York and resumed a more routine concert life, performing new music recitals and joining the downtown improv scene.

And he began to focus his policy on works that he created alone. “It is quite clear that the storms of the 1960s have momentarily subsided, giving way to a period of reflection,” he wrote that year. The first was “The Sheep of Panurge”, which asks an ensemble to play a delicate and ever-changing melody of 65 notes. “Stick together as long as you can, but if you get lost, get lost,” the score mischievously read.

Then came “Coming Together,” in which a lecturer recites a letter written by Sam Melville, one of the leaders of the Attica prison uprising in 1971, on a blustering, minimalist bassline while instrumentalists contribute interjections almost improvised. Mr. Rzewski himself sometimes performed “Coming Together”, playing and speaking simultaneously.

The music is both calculated and urgent; Mr Rzewski described the Attica rebellion, in which 43 people died, as an “atrocity which required every responsible person with the power to shout, to shout”. His many performers have included performance artist Steve Ben Israel, singer-songwriter Julius Eastman and Angela Davis, professor and political activist.

During this period, Mr. Rzewski became involved in the Musicians Action Collective, a coalition that organized benefit concerts for the United Farm Workers, a defense fund for prisoners in Attica, and the Chilean solidarity movement. .

He was quickly drawn to the song “El pueblo unido jamás será vencido”, which had become an anthem of the Chilean resistance thanks to the performances of the group in exile Inti-Illimani. Written by Sergio Ortega and Quilapayún, the song served as the basis for Mr. Rzewski’s series of variations, commissioned for the United States’ Bicentennial and first performed by Ms. Oppens at the Kennedy Center in Washington in 1976.

“People always say, ‘Well, how can music be political if it doesn’t have lyrics?’ Mr. Rzewski told an interviewer that year. “It doesn’t require text. It does, however, require some sort of awareness of the active relationship between music and the rest of the world. “

Returning to Europe in the late 1970s, Mr. Rzewski divided his time between Italy and Liège, where he was a professor at the Royal Conservatory of Music until his death, and regularly traveled to the United States to perform. and teach.

After “The People United”, Mr. Rzewski largely concentrated on solo piano music, such as the “North American Ballads” (1979), which mix baroque counterpoint, minimalist improvisation and popular leftist song. The following major solo works include the “De Profundis” theater, in which a pianist performs while reciting Oscar Wilde’s infamous manifesto on prison; the polystylistic cycle of more than 10 hours “The Road”; and a sprawling series of miniature “Nanosonates”.

“Operas don’t come asking me to write operas,” he told the New York Times in 2008. “Symphony orchestras don’t come asking for symphonies. But there is this pianist that I see every day who keeps asking me for music. So that’s what I do.

Much of the music encourages improvisation and, in performances of canonical works like Beethoven Sonata “Hammerklavier”, Mr. Rzewski created his own elaborate cadences.

He has remained true to his iconoclastic roots. In 2001 he published his sheet music for free download on the Internet, and many are now available on the Petrucci Music Library.

There was, however, a darker side to his wicked personality. Mr. Rzewski could be extremely harsh on students in educational institutions. After the news of his death, several musicians noted on Twitter that he was known for his inappropriate flirtations and sexual innuendo towards younger women.

Mr. Rzewski married Nicole Abbeloos in 1963 and they later separated. His companion for many years was Françoise Walot; they separated around 2008. The survivors include six children, Alexis, Daniel, Jan, Noemi, Esther and Noam, and five grandchildren.

Suspicious of the present, Mr. Rzewski also refused to dwell on nostalgia. “Free improv was going to change the world,” he told The New York Times in 2016, referring to his debut with Musica Elettronica Viva. “It was going to create an entirely new language, so that people could come together from different parts of the planet and communicate instantly.”

After taking a break he added: “Well, sure, we were wrong.”