A tiny audience of mask-wearing music fans gathered in St. Burchardi church in Halberstadt, Germany, on Sept. 5, 2020, to witness an organ chord change. What appeared to be a trivial occurrence turned out to be a watershed moment: In what is known as the world's slowest concert, it was the first sound change in nearly seven years (and only the 14th chord change since the concert began on Sept. 5, 2001). "ORGAN2/ASLSP," John Cage's living legacy, welcomes you.

Cage, who died on his 89th birthday, Aug. 12, 1992, nine years before the concert, left a lasting effect on music composition and is regarded as one of America's best avant-garde composers. Cage, who was born in 1912, studied music with notable figures such as Arnold Schoenberg and Henry Cowell before experimenting with "increasingly unorthodox instruments" such as the prepared piano (a piano with objects placed between or on its strings) and tools such as tape recorders, record players, and radios to create innovative and unconventional sounds and concepts.

"John Cage was an American composer and teacher whose diverse career comprised many works ranging from modern dance to prepared piano and percussion to tape music to aleatory [music containing the element of chance in performance]," says composer Nicolas Lell Benavides in an email. "However, he is primarily known in the Western art music canon as the father of indeterminate music. In its simplest form, indeterminate music is music in which the sound is left to chance. This might be a piece for numerous radios, a set of instructions for performers, or his famous '4:33,' which is considered to be a piece about quiet but is actually a frame for the sounds of the listener's environment. Because the composer is no longer the primary generator of musical ideas, this raises questions about the meaning of music and what it means to be a composer."

In an email interview, Rainer O. Neugebauer, chairman of the board of trustees of the John Cage Organ Foundation, says, "He is one of the most influential musicians of the second half of the twentieth century and he changed modern music." "All sounds, tones, and noises are equivalent in his eyes, and they all have the same value. He was particularly fascinated in the fresh, unexpected sounds he had never heard before."

When it comes to Cage's trademark sound, Neugebauer has a unique way of describing it: "His handling of sound material can be regarded as'decomposition,'" he adds. "Because the composer's subjectivity, his likes and dislikes, needed to be reclaimed, he used a lot of random procedures. He was fascinated by the brilliant diversity of the unstructured, as well as the exhaustion of all formal and structural linkages. He was fascinated by the start of processes whose outcome is unpredictable. He defended the utopia of an unintentional, non-instrumental life, of a basic so-and-so living, of freedom and openness."

"I am for the birds, not for the cages in which people occasionally place them," Cage told The New York Times in 1981 about his book "For the Birds." Cage was alluding to "what we term quiet, which for Cage is merely the absence of intended sounds," according to Neugebauer.

What's the point of a 639-year-long concert?

Cage did not come up with the notion of producing a 639-year-long composition. "Cage composed 'ASLSP' for a piano competition in 1985," Neugebauer explains. "In 1987, he gave it the confusing title 'As SLow aS Possible,' which included an allusion to James Joyce's 'Finnegans Wake"s concluding paragraph, 'Soft dawn, city! Lsp!'." The composition was adapted for the organ at the request of German organist Gerd Zacher, and was dedicated to him as "ORGAN2/ASLSP" (As Slow as Possible).

"In the same year, the first performance in Metz was little over 29 minutes," Neugebauer says. "Following Cage's death in 1998, an organ symposium inquired, "What does as slow as possible mean by an organ?" The sound of a piano string fades away. The organ is a wind instrument, a type of aerophone that can retain a sound for as long as it is fed with air."

Six years after Cage's death, during an organ symposium in Trossingen, Germany, music theorists, philosophers, and organ builders questioned what ASLSP truly meant. 639 years is the answer.

If that seems unusually particular, it's because it is. One of the symposium attendees was aware of a long-abandoned Burchardi chapel in Halberstadt. "And then there was the memory," adds Neugebauer. "Halberstadt had previously written music history: in 1361, composer Michael Prätorius stated that an organ with the first modern keyboard design was built in Halberstadt's cathedral. This organ was the first of its kind to use a manual structured in 12-note patterns, which is still utilised on today's keyboard instruments. As a result, Halberstadt might be considered the cradle of modern music."

According to Neugebauer, the innovation was significant, and American composer Harry Partch referred to it as "that terrible day in Halberstadt." With the new millennium on the horizon, the symposium's thought leaders decided to pay tribute to the historic event. "We then extended the 639 years from 1361 to the year 2000," Neugebaur continues, "with the millennium change as a mirror axis 639 years into the future." "In the year 2640, our performance of John Cage's ORGAN2/ASLSP concludes on time."

"This piece exemplifies John Cage's achievements as a music philosopher and the extremes to which his thought experiments lead us," Benavides comments. "This work's pace is marked 'as slow as possible,' but what does it entail for a decayless instrument? Although the piece is no longer on a human timetable and cannot be performed by a single person, how does this differ from an orchestra or contemporary electronic music? Is it any less of a piece of art because of this? There's something lovely about seeing only a small part of it in a single lifetime, much like how cathedrals and huge monuments take hundreds of years and many lifetimes to build."

Cage released other publications during his life, including "Silence: Lectures and Writings," in addition to this iconic, ongoing work and his other musical masterpieces. He also looked into Zen Buddhism and other Eastern philosophies, coming to the conclusion that "all of the acts that make up music must be understood as part of a single natural process." His long-lasting live concert, on the other hand, remains one of his most awe-inspiring masterpieces.

The composer, according to Neugebauer, would have been discreet about the meaning or message of ORGAN2/ASLSP. "'That is an excellent question,' John Cage would have responded. I don't want to give anything away by answering,' "he declares "And, 'there was a well-known German philosopher named Immanuel Kant, who remarked that there are two things that don't have to imply anything: music and laughter." Cage's response, according to Neugebauer, would have been cagey, alluding to the idea that certain pleasures exist solely for the sake of pleasure.

"Perhaps it's a type of acoustic message in a bottle that's been released into the world," Neugebauer speculates. "Cage's ORGAN2/ASLSP in Halberstadt has been a subversive, irritating, open, and exceedingly delicate art project for 639 years, 'beyond the wit of man...' A dream so oddly set in motion; a former monastery church as a sound dreamspace that permits more than 639 years of the past to become apparent, and that is filled with the force of Ernst-Blochian hope for more than 639 years into the future."