Osvaldo Golijov Fracas Over "Sidereus" Overture Plagiarism? Excessive borrowing? The normal creative process? Suggestions that Osvaldo Golijov, one of today's most sought-after composers, improperly incorporated the work of another composer have stirred up a squall in classical music circles. Critics have weighed in on the subject, prompting a discussion of what exactly is this strange thing called the creative process and whether audiences know exactly what they are getting when an orchestra puts a new piece on the program. The controversy prompted a flurry of sometimes conflicting explanations from Mr. Golijov's defenders and collaborators. On Wednesday, in a telephone interview, Mr. Golijov broke three weeks of silence and offered a spirited defense of his methods. In composing his overture "Sidereus," the Argentine-born Mr. Golijov was said to have borrowed excessively from a work for accordion and ensemble, "Barbeich," by Michael Ward-Bergeman, a composer, accordionist and close friend. Mr. Golijov, however, said that both works, as well as a string quartet he recently wrote, were partly derived from several discarded minutes of a film score that the two composers collaborated on. That movie was "Tetro," a 2009 film directed by Francis Ford Coppola. Mr. Golijov has the film credit for original score, although, he said, Mr. Ward-Bergeman helped out on sections. "There was this beautiful material," Mr. Golijov said. It didn't work for the movie, but it worked for music. We decided both: "Let's grab it. Each one can do what he wants." " He said that the two had worked so closely on the scene that it was impossible to separate who wrote what. "Joint ideas, joint material, same room," he said. Mr. Golijov won a pair of Grammys in 2007 for his opera "Ainadamar" and received a MacArthur Fellowship in 2003. He will be in residence at Carnegie Hall next season and will be an artistic adviser to its Latin American festival. He has long been known for his magpie technique of borrowing from various sources and different musical traditions. And borrowing from other composers in classical music is as traditional as a Gregorian chant. Bach, Schubert and Beethoven all did it. "Sidereus," the subject of this fracas, is a nine-minute overture by Mr. Golijov that was commissioned by a consortium of 35 orchestras to honor a music industry official, Henry Fogel. Mr. Fogel is the former president of the League of American Orchestras, whose board put up $50,000 toward the commission. The orchestras put up another $70,000, said Ryan Fleur, president of the Memphis Symphony and coordinator of the commission. Mr. Golijov received $75,000, with the rest of the money going to production costs. Tom Manoff, a composer and NPR music critic, wrote in his blog that "at least half of the piece" was known to him as "Barbeich" by Mr. Ward-Bergeman, a work for accordion and ensemble. Alex Ross, a critic for The New Yorker, said, "To put it bluntly, "Sidereus" is "Barbeich" with additional material attached." A politic Mr. Golijov said that Mr. Ross's description was "not inaccurate," but continued: "The question is, What is "Barbeich"? What did "Barbeich" come from?" The orchestra league and Mr. Golijov's publisher, Boosey & Hawkes, have stood behind the composer. "Sidereus" has been traveling the country since its first performance by the Memphis Symphony Orchestra in 2010. Next up is a rendition by the Longwood Symphony Orchestra, an amateur group in Brookline, Mass., on March 17. The matter came to light as a result of weird serendipity. Mr. Manoff said he attended a concert by the Eugene Symphony in Oregon with the trumpet player Brian McWhorter to hear a performance of a Haydn trumpet concerto. "Sidereus" happened to be on the program. And it also happened that Mr. McWhorter had recorded trumpet lines for "Barbeich" and had taken a recording to Mr. Manoff, who has a recording studio, for remixing. Mr. Manoff said he had spent 30 hours with "Barbeich." "As the phrases unfolded, McWhorter and I would turn to one another with a genuine sense of shock," Mr. Manoff wrote on his blog. Our spontaneous reactions were also surreal and even funny. After the concert we asked each other, "Did this really happen?" " "Sidereus" contains important elements of Mr. Ward-Bergeman's "Barbeich," Mr. Manoff said, including melodies, harmonies, counterpoint, musical structures, textures and form. That is far more than Mr. Golijov openly described on his publisher's Web site. "For the "Moon" theme," Mr. Golijov wrote, "I used a melody with a beautiful, open nature, a magnified scale fragment that my good friend and longtime collaborator, accordionist Michael Ward-Bergeman, came up with some years ago when we both were trying to come up with ideas for a musical depiction of the sky in Patagonia." That, he said in the interview, referred to a scene in the film. James McQuillen wrote the program notes for the Eugene Symphony performance, based on the description. "I feel suckered," he said in a blog posting. Mr. Golijov acknowledged that using the word "melody" was a simplification. "I thought that was enough," he said.