Keystone via Associated Press,file, Sigi Tischler
FILE - In this Sept. 6, 2007 file picture French composer and conductor Pierre Boulez conducts the Lucerne Festival Academy Orchestra in Lucerne, Switzerland. Former New York Philharmonic principal conductor Pierre Boulez, who moved among conducting, composition and teaching over a long career that made him one of the leading figures in modern classical music, has died at age 90. A spokesman for the Paris Philharmonic confirmed that Boulez had died in Baden-Baden, Germany.

FRANKFURT, Germany — Pierre Boulez, the former principal conductor of the New York Philharmonic who moved between conducting, composition and teaching over a long career that made him one of the leading figures in modern classical music, has died at age 90.

A spokesman for the Paris Philharmonic, Hamid Si Amer, confirmed Wednesday that Boulez died the previous day in Baden-Baden, Germany.

"Pierre Boulez made French music shine throughout the world," French President Francois Hollande said in a statement. "As a composer and conductor, he always wanted to reflect on his era."

Born in Montbrison, France, on March 26, 1925, Boulez initially studied mathematics as a youth before switching to music. He studied harmony at the Paris Conservatory with composer Olivier Messiaen and had lessons from Rene Leibowitz in the dissonant 20th-century style known as twelve-tone composition. His compositions include the Second Piano Sonata from 1947-48 and "Le Marteau Sans Maitre (The Hammer Without A Master), a setting of surrealist poetry by Rene Char for six instruments and alto voice.

He turned more and more from composition to conducting, leading the New York Philharmonic, where he succeeded Leonard Bernstein, and the BBC Symphony Orchestra during the 1970s.

He led Wagner's "Ring" cycle of operas at the Bayreuth Festival Theater and also worked with the Chicago Symphony, the Cleveland Orchestra, Orchestre de Paris and the London Symphony Orchestra. His recordings won more than 25 Grammys.

In 1977, he launched IRCAM, a Paris-based institute focused on music, acoustics and electronics.

Boulez was a cool and contained presence on the podium, preferring a dark business suit and tie to tuxedo and tails, his gestures communicating logic and precision.

He had a reputation as an uncompromising modernist who rejected easy ways of pleasing audiences. In a 2010 interview with Philip Clark for classical music publication The Gramophone, Boulez described the more conventional music of American composer Aaron Copland as "folklore and dance" and dismissed German composer Paul Hindemith by saying his music "is very well put together, yes" but "says nothing to me."

Yet as a conductor Boulez ranged well beyond the confines of modernism, often favoring Romantic audience favorites such as Bruckner, Mahler and Wagner. For some of his last recordings he chose the lush, moody works of early 20th century Polish composer Karol Szymanovski.

"I may be wrong, but I equate music with culture," he was quoted as saying in the Gramophone interview. "I don't think music is an entertainment product. It's a product of culture — not for marketing, but to enrich lives."

"All these years, I've been trying to convince people that music is not there to please them; it's there to disturb them."

Hinnant reported from Paris.