Elliott Carter’s recent orchestral music is a synthesis of synergetic sound and syntactical brilliance, a culmination of more than seven decades of original, cutting-edge ideas. When the Monadnock Festival Orchestra finished playing the American premiere of Carter’s Symphonia in Sanders Theatre last week, there was no question that one of the most important music events of recent times had just taken place. This is tough, gritty music that demands the most attentive of listeners, and the 50-plus minutes of Symphonia were at times overwhelming.

At 93, Carter ’30 continues to dazzle with a stream of new works. He wrote his first opera two years ago and Yo-Yo Ma ’76 recently premiered his cello concerto with the Chicago Symphony. His intense but accessible modernism is a welcome change from the watered-down simplicity of many of today’s new orchestral works. Symphonia, subtitled Sum fluxae pretium spei (“I am the prize of flowing hope” from 17th-century metaphysical poet Richard Crashaw’s “Bulla”), actually existed as three separate pieces before Carter combined them into one work.

The movements were written for the Chicago Symphony Orchestra, the BBC Symphony Orchestra and the Cleveland Orchestra; Carter worked on them from 1992 to 1996. Although Oliver Knussen and the BBC Orchestra premiered and recorded Symphonia in its entirety on Deutsche Gramophone, the work as a whole had never been played in the U.S. until last week.

The first movement Partita is, as the title suggests, a tapestry of diverse musical ideas coherently woven together. There are contrasting sections ranging from highly rhythmic and jagged themes to lyrical passages, and all are seamlessly intertwined. There are hints of solo passages—a flute here followed by an English horn there. The slow-moving second movement, Adagio tenebroso, involves an obsession with certain intervals, especially the perfect fifth. Huge differences in register (for example, the pairing of piccolo with double bass and low brass) provide for a sense of gravity and struggle. The final movement, Allegro scorrevole (“flowing easily,” one of Carter’s favorite indications), is a lively and brilliantly orchestrated finale. The work ends with a lone, high A-flat in the piccolo, a shrill, satisfying conclusion.

The Monadnock Festival Orchestra, under the direction of James Bolle, gave a vigorous and virtuosic performance. The rhythmic difficulty of the work was most visible through concertmaster Ole Bohn’s arm and bow gestures before entrances. An enthusiastic audience greeted the work with a standing ovation, which Carter acknowledged from the stage.

The concert was a celebration of Music Director Bolle’s 70th birthday and was presented in collaboration with Harvard College’s Music department. In his notes on the concert, Bolle said that it “represents for me the ne plus ultra of the kind of programming I have striven to achieve in the 35 seasons of Monadnock music.” He certainly accomplished that task and deserves much praise for the committed performance he and the orchestra gave of Carter’s masterpiece, as well as the orchestra’s devotion to contemporary music.

After intermission, pianist Konstantin Lifschitz performed Brahms’ First Piano Concerto. This was 25-year-old Lifschitz’s overdue Boston debut but the result was somewhat disappointing, especially after such an explosive first half. When Lifschitz released his recording of Bach’s Goldberg Variations at the age of 16, he drew comparisons with the great Glenn Gould. One could also make an association with Gould based on his Brahms performance: both pianists took the work at almost unbearably slow tempi. Unlike Leonard Bernstein, who performed the work with Gould in 1962, James Bolle did not preface the performance with a disclaimer on artistic differences. The first movement was too long, aimless and lacking in a sense of overarching structure, as every quarter-note beat was pounded out. Lifschitz succeeded much better in the lyrical middle movement, but it was back to slow, calculated playing in the final movement. Luckily, Carter’s Symphonia had left such a strong impression that the problematic Brahms could not eclipse the memory of its grandeur.