Classical composer George Rochberg, 86, who was propelled by private tragedy to defy the prevailing style of composition of his time and, in so doing, helped usher in a new era of musical romanticism, died May 29 at a hospital in Philadelphia of complications following surgery earlier in the month. He lived in Newtown Square, Pa.

After a quarter-century as a respected academic composer in the "serial" or "12-tone" style propounded by Arnold Schoenberg and Anton von Webern in the 1930s and 1940s, Mr. Rochberg broke free in the late 1960s and never looked back.

Early in his career, he wrote in the accepted atonal style -- without easily identifiable melodies -- of the time, as well as the rigorous mode of serialism, in which compositions were built around repeated series of predetermined notes. But after the death of his 20-year-old son from a brain tumor in 1964, Mr. Rochberg (pronounced "ROCK-berg") entered a period of deep reflection and self-doubt.

He emerged with a new style of unabashedly romantic music, filled with soaring melodies and sonorous harmonies, that was a full-force renunciation of both serialism and "aleatory" music, in which random sounds became part of a musical work. It was nothing less than a declaration of artistic independence.

Mr. Rochberg's new works, which reached their highest point with a series of string quartets in the 1970s, his 1975 Violin Concerto and his Fifth and Sixth symphonies in the 1980s, initially brought him scorn from established academic composers and critics who saw his music as a betrayal of the principles of modernism. He was called "cowardly" and "Victorian" for composing music that borrowed freely from Schubert and Mahler.

"I had openly defected, without apology," he explained to the New York Times in 1997. "But I was dissatisfied with the narrow strictures within which musical thought could take place. Basically, Serialism is an ice-cold, stingy, parsimonious form of human expression."

Mr. Rochberg's music, which was ultimately considered more interesting than that of an ossified avant-garde, proved popular with performers and concertgoers, who found a refreshing return to the fundamentals of melody and form that had been the bulwark of Western music since the Renaissance.

"There is no greater provincialism," he wrote in a 1969 essay, "than that special form of sophistication and arrogance which denies the past."

Mr. Rochberg, the son of Ukrainian immigrants, was born in Paterson, N.J., and grew up in nearby Passaic. He wrote songs in high school with friend Bob Russell, who later wrote lyrics for Duke Ellington. Mr. Rochberg worked his way through Montclair (N.J.) State University playing piano in jazz bands and later studied at the Mannes Music School in New York with conductor and composer George Szell. He wrote a few pop songs under an assumed name before becoming an Army infantry officer in World War II, during which he was wounded in battle in Normandy.

After the war, he studied at the Curtis Institute of Music in Philadelphia and, in 1949, received a master's degree from the University of Pennsylvania. He studied in Rome on a Fulbright fellowship in the early 1950s and spent several years on the Curtis faculty. During the 1950s, he was an editor for a Philadelphia music publishing company before teaching at Penn from 1960 to 1983.

His early works were well accepted -- the New York Philharmonic premiered his "Night Music" in 1953, and his first two symphonies debuted with the Philadelphia Orchestra and the Cleveland Orchestra, respectively -- but Mr. Rochberg and his audiences found greater satisfaction with his more traditional-sounding later works.

His lyrical Third String Quartet elicited almost open-jawed amazement from New York Times critic Donal Henahan when it premiered in 1972: "Mr. Rochberg's quartet is -- how did we used to put it? -- beautiful."

When Mr. Rochberg's Symphony No. 6 premiered in Pittsburgh in 1987, the audience gave it a 10-minute ovation. Since he broke with the orthodoxies of the 12-tone style, other composers, including David Del Tredici and John Corigliano, have taken up the neo-romantic banner.

"Rochberg boldly challenged the music world's status quo," critic Michael Linton wrote in the journal First Things in 1998, "and his challenge has resonated through the ensuing decades, shifting the profile of modern music at the century's close into a shape that thirty years ago would have been unthinkable."

Among more than 100 works, Mr. Rochberg composed six symphonies, seven string quartets, concertos for violin, clarinet and oboe, as well as an opera.

He also wrote a book of essays, "The Aesthetics of Survival: A Composer's View of 20th-Century Music," published in 1984 and reissued last year. At the time of his death, he was completing an autobiography and a technical book about music theory.

Survivors include his wife of 64 years, Gene Rochberg; a daughter; and two grandchildren.

George Rochberg, foreground, and George Crumb are two Philadelphia composers who changed the direction of American music during the 1970s.