AIX-EN-PROVENCE.- Voltaire and Jean-Philippe Rameau looked so much alike, how could they not have ended up as collaborators? An 18th-century drawing shows them bowing to each other, mirror images of gangly bodies and jutting chins.

Sealed by resemblance, the pairing of this pioneering philosopher and pioneering composer, two of Enlightenment France’s most important cultural figures, was exuberant — at least at first. “Don’t have children with Madame Rameau, have them with me,” Voltaire wrote to his partner, in a sly allusion to the works he wanted to create together.

Their first opera, “Samson,” opened Thursday in an intense and moving performance at the Aix-en-Provence Festival, set in the crumbling ruin of a once-grand hall. But this “Samson” is not the one Rameau and Voltaire wrote. The original score was lost some 250 years ago, so the Aix production — the work of conductor Raphaël Pichon and director Claus Guth — is a quiltlike assemblage drawn from other Rameau pieces, with a largely new text inspired by the biblical Samson story.

The crucial challenge of such a pastiche is making a sewed-together amalgam feel like an organically flowing work. “There are questions of connection,” Pichon said in an interview. “The tonal relationships between everything, the harmonic journey, the details of orchestration.”

But performed with relish by Pygmalion, Pichon’s period-instrument orchestra and choir, this “Samson” retains the hypnotic continuity of Rameau’s complete operas, their steadiness and also their variety, veering from festive to soulful, from raucous dances to hushed, hovering arias and radiant choruses.

“It’s really a contemporary object, an object from now,” Pichon said. “But also connected to that original intention, trying to respect the first intuition of Voltaire and Rameau.”

In the early 1730s, the two men traveled in the same elite circles in Paris. The idea for them to join forces emerged as Rameau was basking in the success of his first opera, “Hippolyte et Aricie,” with its fiercely debated innovations. Voltaire had also had a recent hit, the play “Zaïre”; he was a newcomer to libretto writing but fascinated by Rameau’s music.

At first, Rameau hotly pursued a reluctant Voltaire, who protested in a letter, “I don’t believe I have the talent to write lyrics.” Even after being convinced, Voltaire still dragged his feet, and his work on the text was temporarily derailed when he had to flee Paris for the countryside after the 1734 publication of his dangerously progressive “Lettres Philosophiques.”

“Rameau rants, Rameau claims that I’ve cut his throat, that I treat him like a Philistine,” Voltaire complained as the composer demanded an allegorical prologue (then standard in opera) and other adjustments to soften the libretto’s modernizing impulses. Voltaire, for his part, pressured Rameau to break with French convention and write more Italian-type arias: “I want ‘Samson’ to be in the new style,” he wrote.

A year after they started, the piece was well enough along to be previewed in a private concert performance. It was dicey, though, to produce stage works on sacred themes in a Catholic country, and the word from the censors was no. Rameau, to Voltaire’s chagrin, grew distracted by other projects, including the sprawling opera-ballet “Les Indes Galantes,” in which he might have included some of the music he had just written for “Samson.” (Composers of that era were great self-recyclers.)

Voltaire finally finished the text in 1736, but the censors rejected it again. Rameau was by then onto his next opera, “Castor et Pollux,” for which he probably also borrowed from “Samson.” His work with Voltaire seemed to be over, and a few years later, he took a pass on the writer’s new libretto, “Pandore.”

But in 1745, Rameau contributed an hour of incidental music to a lightweight play by Voltaire celebrating the marriage of the king’s son. The same year, the two men produced — with less acrimony than had become their norm — “Le Temple de la Gloire,” an allegorical commemoration of a French military victory.

But, at least for Voltaire, these pieces paled in comparison to “Samson,” which he said contained sounds both “awe-inspiring and graceful”: “I dare to think that, in spite of a weak text, it was Rameau’s masterpiece.”

Who wouldn’t want to hear the masterpiece of one of history’s greatest composers? But while Voltaire preserved a version of the “Samson” libretto when his complete works were published, Rameau’s score disappeared. All that remains are the scant speculations about bits that he reused later.

A reconstruction would be impossible, but Pichon and Guth were game for something more unconventional, if also essentially old-fashioned: It was all the rage in Rameau and Voltaire’s time to create pastiches using cobbled-together buffets of preexisting music to tell familiar stories.

Rameau’s stage works, his mixture of refinement and energy, are familiar territory for Pichon and Pygmalion. And Guth is a veteran experimenter with older repertory; recently, in “Doppelganger” at the Park Avenue Armory in New York City, he staged Franz Schubert’s “Schwanengesang” as a moody dreamscape in a soldiers hospital.

“I’m always happy if I can have a new perspective on what we’re doing when we do music theater,” Guth said in an interview. “Not just playing an opera from beginning to the end in the usual way.”

Their “Samson” is set in a bombed-out ballroom in a stylized vision of the present day; the plot’s Israelites and Philistines, warily intermingling, inevitably evoke the conflicts of our time.

Pichon and Guth have reached further back in the biblical story than Voltaire’s libretto or other adaptations such as George Frideric Handel’s oratorio “Samson” and Camille Saint-Saëns’ opera “Samson et Dalila.” (The action in those pieces doesn’t start until halfway through the Aix production.) An actress portrays Samson’s elderly mother, reciting passages from Colm Tóibín’s novel “The Testament of Mary” (2012), which is narrated from the perspective of Jesus’ mother.

Samson here is something of an “X-Men” figure, realizing from childhood that he’s different: endowed with superhuman strength but also prone to catastrophic acts of violence that ruin his early, pre-Delilah marriage to another Philistine woman, Timna. More than the traditional melodrama of seduction, this “Samson” is the tragedy of a hero’s inability to live in the world.

There are more than 60 numbers, including selections from works in which Rameau may have used “Samson” music, including “Les Indes Galantes,” “Castor et Pollux,” “Les Fêtes d’Hébé” and, especially, the vividly dramatic “Zoroastre.” There are parts of later Voltaire collaborations, “Le Temple de la Gloire” and “Les Fêtes de Ramire.” “Anacréon,” a section of “Les Surprises de l’Amour,” is mined for having, as “Samson” might have, a low-voice protagonist rather than the standard high-tenor “haute-contre.” The emotional climax, as Delilah mourns her betrayal, is the aching instrumental “Entrée de Polymnie” from “Les Boréades.”

The original words have been changed by Pichon, Guth and their team — sometimes lightly, sometimes substantially — to tell the new story, while retaining a formal, 18th-century character and the precision of French Baroque text setting. “It is under the influence of the lexicon of Voltaire,” Pichon said. “We tried to make it close to his world.”

A darkly rumbling, groaning electronic soundscape, designed by Mathis Nitschke, unsettlingly punctuates some scenes. “There’s a dialogue between the Rameau music and more contemporary sounds,” Guth said. “Behind all this is my aim to get out of this kind of ‘I buy my ticket and I’m sitting in a Baroque opera and I know what the next two hours will sound like.’ Here, you have to open your ears again every 10 minutes.”

Mezzo-soprano Lea Desandre (Timna) and soprano Jacquelyn Stucker (Dalila) are both exquisitely sensitive in their floating music. As Samson, baritone Jarrett Ott lacks the juicy low notes to fully command but is remarkably steady in a demanding role.

Demanding because of the music and because of the process of creation: Major changes to the piece, which arrived constantly through rehearsals, continued so late that a revised order of the selections was included as an insert in the program on opening night.

There might be room for more tweaks. The ending, in particular, while it hews to Voltaire’s intention of abruptness, feels rushed and anticlimactic after the patient accumulation of so much sober power. But Pichon and Guth have conjured a sense of the beauty that made Voltaire so nostalgic about the opera.

“I never think of Rameau’s music,” he wrote, “without looking back wistfully to ‘Samson.’”

This article originally appeared in The New York Times.