NEW YORK, NY.- Hector Berlioz did not have the twilight of a great composer.

In his memoirs, he described himself in his 60s as “past hopes, past illusions, past high thoughts and lofty conceptions.” His extraordinary but unusual music was unloved and unplayed; a widower two times over, he was lonely, and hated people more than ever. He wrote, with a shake of his fist at the sky: “I say hourly to Death, ‘When you will.’ Why does he delay?”

He felt wronged by the public and his fellow composers, who even when they admired him didn’t know what to do with his music, or his personality. Wagner wrote that Berlioz didn’t trust anyone’s opinion and seemed to enjoy isolation, dooming him to “remain forever incomplete and perhaps really shine only as a transient, marvelous exception.”

Berlioz had faith that his time would come, though. By his estimate, things would pick up for him if he could just live to 140. He made it to 65.

But he wasn’t wrong. After his death, in 1869, some of his works, like the “Symphonie Fantastique,” became firmly entrenched in the canon, and he is the subject of this year’s Bard Music Festival, which begins Friday. Still, two weeks’ worth of concerts and panel discussions, as well as a companion collection of essays, can only begin to capture the breadth of Berlioz’s artistry.

There is Berlioz the composer, of course, but also Berlioz the critic, the conductor, the impresario, the philosopher and the literary author. A focus on his music alone is just as dizzying: Nearly every work defies conventional analysis and taxonomy, and must be approached on its own terms.

His idiosyncratic music didn’t truly catch on until the mid-20th century, and even then fitfully. His operas remain too difficult to stage regularly, and many of his concert works are too strange to program or market to audiences. It feels as though we are still catching up to Berlioz’s pipe-dream visions of musical possibility.

BERLIOZ WAS BORN in La Côte Saint-André, in the south of France; in his memoirs, he humorously notes that his birth lacked the poetic magnitude of a Virgil or Alexander the Great. “Can it be,” he wrote, “that our age is lacking in poetry?”

He carried himself with that blend of grand self-regard and disdain for others throughout his life. When he moved to Paris to study, first medicine and then composition, Berlioz found the city’s cultural life crude, lowbrow and industrial. He wrote of Parisians, “They want a score that, like a plate of macaroni, can be assimilated immediately without their having to think about it or even pay attention to it.”

Naturally, he had the right ideas about music. His taste, though, wasn’t exactly modern. He would come to adore Ludwig van Beethoven and to embody the Romantic era, doing for music what Eugene Delacroix did for painting. But the greatest composers, in Berlioz’s opinion, were more Classical, like Gaspare Spontini, Luigi Cherubini and, above all, Christoph Gluck.

Berlioz’s family had a piano, but he never learned to play it (a gap in his artistry that others would later point to as the reason for his unconventional orchestration); he taught himself to compose, and he read treatises on harmony. While still a medical student, he made copies of Gluck’s operas by hand. But knowing he could get only so far without formal study, he became a private pupil of Jean-François Le Sueur at the Paris Conservatory.

Almost none of his music from that time survives, but what does is impressive. He started to write, but never finished, an opera, “Les Franc-Juges,” whose extant overture is sophisticated and dramatically effective, already bearing the rhythmic and timbral hallmarks of coming masterpieces.

The first of those was the “Symphonie Fantastique,” which like many Berlioz works is freely structured and poetically named. (The subtitle is “Episode in the Life of an Artist ... in Five Parts.”) Audiences welcomed this piece from the start, and it remains his most famous. It looks back to Beethoven’s evocative “Pastoral” Symphony, yet ahead to Wagner’s leitmotif-driven operas, to tell a story of unrequited love and opium-induced hallucination. The object of the artist’s affection is represented by a musical cue that Berlioz called the idée fixe; it recurs throughout the movements, which flow from a ball to a field, to the guillotine and a hellish witches’ Sabbath.

Most of the large-scale works that followed were different from one another, and from anything else on the stages of Paris, where Berlioz still struggled to cement his place in the establishment. He did gain the admiration of some important composers. Franz Liszt was an unwavering champion; Felix Mendelssohn enjoyed elements of his music, and liked him personally, but couldn’t make sense of his scores.

That’s no easy task. Berlioz wrote a sequel to the “Symphonie Fantastique” called “Lélio, or the Return to Life,” a work for a narrator, a chorus with soloists, an orchestra and a pianist. After briefly recalling the idée fixe of the symphony, it sprawls with thoughts on love, literature and music. Like Johann Goethe’s “Faust, Part II,” Berlioz’s follow-up to his hit is unwieldy and delirious, sometimes great but mostly baffling.

Berlioz’s contemporaries similarly didn’t know what to make of “Harold en Italie,” a George Byron-inspired symphony that could also be described as a tone poem, or a viola concerto. His “Roméo et Juliette” was a “dramatic symphony” in seven movements, with a chorus and vocal soloists, famous for its “Queen Mab” Scherzo. As scholar Jacques Barzun wrote, Berlioz doesn’t illustrate the drama or depict “the song of the larks or the nurse’s knock on Juliet’s door. But there is every reason to think that he was at one with his author in his views on love.”

So persuasively did Berlioz represent love that “Roméo” opened the mind of Richard Wagner, who was a decade younger and still several years from his breakthrough with “Der Fliegende Holländer.” David Cairns, the reigning authority on Berlioz, wrote that when Wagner heard the piece he was overwhelmed and felt that it revealed “till then unimagined possibilities of musical poetry.” What he received, Cairns added, “he would give back in ‘Tristan und Isolde.’”

If only Berlioz admired “Tristan” in turn. He once referred to it as a “chromatic moan.” Wagner, though, was just one of many composers on the receiving end of Berlioz’s barbed wit. He was a prolific critic, arguably the most brilliant, unsparing writer on music of his age. Of Donizetti’s “La Fille du Régiment” he wrote, “There is harmony, melody, rhythmic effects, instrumental and vocal combinations; it’s music, if you will, but not new music.” But he had an eye for young talent, championing Charles Gounod, Camille Saint-Saëns and Georges Bizet early in their careers.

Berlioz also wrote a treatise on instrumentation. (One comment, about the English horn evoking memory and distance, would seem to describe Act 3 of “Tristan” decades before its premiere.) And he was shockingly modernist in the often hilarious “Evenings in the Orchestra,” a hybrid book of satire, memoir and science fiction, including an in-depth vision for a musical utopia called Euphonia, in the year 2344.

He was a reluctant critic, though, and saw himself less as a critic and more as a newspaper “feuilletonist.” He described the difference, resonant to this day, in his memoirs: Critics, he wrote, publish only when they really have something to say, “to illuminate some question, challenge some theory, bestow well-mannered praise or blame.” Feuilletonists, on the other hand, are assigned reviews, which means they often hold no strong opinions about what they cover, though they have to behave as if they did.

Berlioz saw workaday reviewing as nothing more than a source of income; much Parisian music around him, he thought, warranted neither his nor the public’s attention. “From time to time,” he wrote to his father, “I lose patience and crush two or three mediocrities in my fist.”

DESPITE THE POWER of his pen, Berlioz failed to shift public opinion about his own music. He continued to write innovative masterpieces: the pre-Mahlerian “Grande Symphonie Funèbre et Triomphale”; the otherworldly “Grande Messe des Morts”; the dramatic yet defiantly symphonic “Damnation de Faust.” As Philip Glass and Steve Reich would a century later, Berlioz had his music performed mostly by gathering players and organizing concerts himself. He described a trip to Germany as “ruinous” because he traveled with 500 pounds of scores.

It would seem, with his gifts for vocal writing and his foundational love for Gluck, that he would find the most success in the opera house. But he struggled there the most. Berlioz composed only three operas, and heard only two of them: the early “Benvenuto Cellini,” which is challengingly virtuosic even for performers today, and the late, lithe “Béatrice et Bénédict,” an opéra comique that is difficult to stage without a French cast because of its spoken dialogue of Shakespearean complexity.

Berlioz must have been certain of his skill as an opera composer, though. After finishing his magnum opus, “Les Troyens,” he wrote to his sister, “There are inventions in it that, unless I am pathetically mistaken, will make the musicians of all Europe prick up their ears, and perhaps make their hair stand on end.” He never heard a full performance of it in his lifetime; he was forced to split its five acts into effectively two operas, and to stage a truncated version of the second part.

“Les Troyens” resembles grand opera but is more sophisticated than the best of the genre. An adaptation of Virgil’s “The Aeneid,” it thrillingly recounts the fall of Troy in its first two acts, and then the tragic romance of Dido and Aeneas in the luxuriously relaxed, perfumed remaining acts. Unusually for grand opera, the subject is mythic rather than historical, the characters more symbolic than human, and, more like Wagner, the plot is straightforward while resisting any single interpretation.

Different versions of “Les Troyens” were presented after Berlioz’s death, but the full score wasn’t published until the mid-20th century, when it was staged in its entirety for the first time. To this day, it’s a rarity, even in Paris, but a privilege to see and hear.

Given the costs of opera, it’s understandable that “Les Troyens” isn’t produced often. But what of Berlioz’s other works? The world has mostly come around on his worth; a wave of reappraisals a century ago cemented his legacy. And yet his music remains too challenging for viability.

The “Symphonie Fantastique” fits on a standard orchestral program, but not much else, making each Berlioz performance feel like a special occasion. At Bard, a series of concerts and discussions, based on themes of Romanticism and literature, will include pieces that most likely won’t be played elsewhere in the United States this season.

Perhaps such scarcity will always be the case. Berlioz’s contemporary Ferdinand Hiller poetically reasoned that this was because he “does not belong in our musical solar system.” He was more like a passing comet, brilliant and uncanny. “Will anything like him show up again in the musical sky?” Hiller asked. “That is a possibility neither to be hoped for nor feared — nor, indeed, imagined.”

This article originally appeared in The New York Times.