Cover of the score of La prise de Troie, the first two acts of Les Troyens.

Les Troyens (in English: The Trojans) is a French opera in five acts by Hector Berlioz.

The libretto was written by Berlioz himself on the basis of Vergil's epic poem The Aeneid.

Written between 1856 and 1858, Les Troyens was Berlioz's largest and most ambitious work, and the summation of his entire artistic career, but he never saw the work performed in its entirety during his lifetime. Under the title Les Troyens à Carthage, the last three acts were first performed, with many cuts, in Paris on 4 November 1863. It was played 21 times.

Berlioz had a keen affection for literature, and he admired Vergil since his childhood. In his memoirs, he gives a detailed account of how he embarked upon an opera based on The Aeneid:

I happened to be in Weimar with the Princess Wittgenstein, a devoted friend of Liszt's, a woman of rare intelligence and feeling, who has often comforted me in my fits of depression. Something led to me to speak of my admiration of Virgil and of an idea I had formed of a grand opera on the Shakespearean model, to be founded on the second and fourth books of The Aeneid. I added that I was too well acquainted with the necessary difficulties of such an undertaking ever to attempt it. "Indeed," replied the Princess, "your passion for Shakespeare, combined with your love of the antique, ought to produce something grand and uncommon. You must write this opera, or lyric poem, or whatsoever you choose to call it. You must begin it, and you must finish it." I continued my objections, but she would hear none of them. "Listen", said she. "If you are shirking the inevitable difficulties of the piece, if you are so weak as to be afraid to brave everything for Dido and Cassandra, never come to see me again, for I will not receive you." This was quite enough to decide me. On my return to Paris, I began the poem of Les Troyens. I attacked the score, and after three years and a half of corrections, changes, additions, etc., I finished it.

On 3 May 1861, Berlioz wrote in a letter: "I am sure that I have written a great work, greater and nobler than anything done hitherto." Elsewhere he wrote: "The principal merit of the work is, in my view, the truthfulness of the expression." For Berlioz, truthful representation of passion was the highest goal of a dramatic composer, and in this respect he felt he had equalled the achievements of Gluck and Mozart.

In his memoirs, Berlioz described in excruciating detail the intense frustrations he experienced in seeing the work performed. For five years (from 1858 to 1863), the Paris Opéra -- the only suitable stage in Paris -- vacillated. Finally, tired of waiting, he agreed to let a smaller theater, the Théâtre Lyrique, mount a production. However, the management, alarmed at the size, insisted he cut the work in two. It mounted only the second half, given the name Les Troyens à Carthage. Berlioz noted bitterly: "it was manifestly impossible for them to do it justice... the theater wasn't large enough, the singers insufficiently skilled, the chorus and orchestra inadequate." Many compromises and cuts where made and the resulting production "an imperfect" one. In view of all the defects, Berlioz lamented "in order properly to organize the performance of so great a work, I should have to be as absolutely master of the theater as I am of the of the orchestra when rehearsing a symphony."

Even its less than ideal form, the work made a profound impression; musicians like Meyerbeer attended night after night. A friend tried to console him for having had to endure so much in the mutilation of his magnum opus and pointed out that after the first night the audiences were increasing. "See," he said encouragingly to Berlioz, "they are coming." "Yes," replied Berlioz, feeling old and worn out, "they are coming, but I am going."

Berlioz never saw the first two acts, given the name La prise de Troie, performed. The first five-act performance of Les Troyens, spread over two nights, only took place at Karlsruhe in 1890, long after Berlioz's death. In subsequent years, wrote British Berlioz biographer David Cairns, the work was thought of as "a great sprawling white elephant, product of declining creative vitality, beautiful in patches, but fatally uneven, and quite unstagable -- part from anything else, because of its length."

It was only in 1957 in a production at the Royal Opera House, Covent Garden conducted by Rafael Kubelík that Les Troyens was staged more or less as Berlioz conceived it. It was finally recorded in its entirety in 1969 by the British conductor Colin Davis.

Les Troyens was staged again in 1990 for the opening of the new Bastille Opéra in Paris. It was a half-success, because the new opera could not be quite ready on opening night, which caused trouble during rehearsals. The performance had several cuts, including the dances in the third act.

To mark the centenary of Berlioz's birth in 2003, Les Troyens was revived in productions at the Théâtre du Châtelet in Paris (conducted by John Eliot Gardiner), Amsterdam (conducted by Edo de Waart), and at the Metropolitan Opera (with the highly acclaimed American mezzo-soprano Lorraine Hunt Lieberson as Dido).

Only knowing the work from a piano score, the British critic W.J. Turner declared the Les Troyens "the greatest opera ever written" in his 1934 book on Berlioz, much preferring it to the much more popular works of Richard Wagner. American critic B.H. Haggin heard in the work Berlioz's "arrestingly individual musical mind operating in, and commanding attention with, the use of the [Berlioz] idiom with assured mastery and complete adequacy to the text's every demand". David Cairns described the work as "an opera of visionary beauty and splendor, compelling in its epic sweep, fascinating in the variety of its musical invention... it recaptures the tragic spirit and climate of the ancient world." Hugh Macdonald said of it:

In the history of French music, Les Troyens stand out as a grand opera that avoided the shallow glamour of Meyerbeer and Halevy, but therefore paid the price of long neglect. In our own time the opera has finally come to be seen as one of the greatest operas of the 19th century.

There are several recordings of the work, and it is performed more and more often. A brief excerpt of an aria from it was featured in the film Star Trek: First Contact.