Dardanus is an opera by Jean-Philippe Rameau with a French-language libretto by Charles-Antoine Leclerc de La Bruère. It takes the form of a tragédie en musique in a prologue and five acts. Dardanus premiered at the Paris Opéra on 19 November 1739 to mixed success, mainly because of the dramatic weakness of the libretto. This caused Rameau and La Bruère to rework the opera, completely rewriting the last three acts, for a revival in 1744. Only when Dardanus was again performed in 1760 did it win acclaim as one of Rameau's greatest works.

The original story is loosely based on that of Dardanus, the son of Zeus and Electra, and ancestor of the Trojans. However, in the opera, Dardanus is at war with King Teucer, who has promised to marry his daughter Iphise to King Anténor. Dardanus and Iphise meet through the intervention of the magician Isménor and fall in love. Dardanus attacks a monster ravaging Teucer's kingdom, saving the life of Anténor who is attempting, unsuccessfully, to kill it. Teucer and Dardanus make peace, the latter marrying Iphise.

Dardanus appeared at a time when the quarrel between Rameau's supporters and those of the operas of Jean-Baptiste Lully had become ever more embittered. Rameau's stage music had been controversial since his debut in 1733 with Hippolyte et Aricie. His opponents - the so-called lullistes - were conservatives who accused him of destroying the French operatic tradition established by Lully under King Louis XIV in the late 17th century. Yet they could not dissuade the Paris Opéra from offering Rameau commissions for new works. Hippolyte had been followed by Les Indes galantes in 1735 and Castor et Pollux in 1737. In 1739 the Opéra commissioned Rameau to write not one but two new scores, the opéra-ballet Les fêtes d'Hébé, which premiered on 21 May, and Dardanus. This could only inflame the controversy and there were many lullistes eager to see Rameau fail.

It is likely that Rameau did not start work on the music of Dardanus until after the premiere of Les fêtes d'Hébé, so that he must have completed it in five months or less. There is some evidence that initially Voltaire had been considered as the librettist for the new opera but he did not have a finished text to hand and so he may have suggested using Dardanus by Leclerc de La Bruère instead. La Bruère was only 23 but he had already written four opera libretti, although none were as lengthy or weighty as Dardanus. From the start critics attacked Dardanus, not for the quality of its verse, but for its dramatic incoherence. They accused La Bruère of stringing together a series of spectacular scenes - magical incantations, a dream sequence, the appearance of a monster - without any regard for dramatic logic and thus creating a hybrid between tragédie en musique and opéra-ballet, a lighter genre in which connection between the acts was of little importance. The drama of two lovers divided because they came from warring nations also resembled the plots of two recent tragédies en musique: Royer's Pyrrhus (1730) and Montéclair's Jephté (1732). Yet, according to the Rameau specialist Sylvie Bouissou, Dardanus suffers in comparison with these models, lacking their dramatic intensity and genuinely tragic endings (in Pyrrhus the heroine kills herself and in Jephté the lover of the title character's daughter is struck down by God).

Dardanus premiered on 19 November 1739 and ran for 26 performances. This meant it was not a great success but neither was it the outright failure for which the Lullistes had hoped. Rameau and La Bruère responded to criticism by making alterations to the work during its first run. Dardanus was soon the target of two parodies: Arlequin Dardanus (premiered at the Comédie-Italienne on 14 January 1740) by Charles-Simon Favart and Jean des Dardanelles by Jean-Baptiste-Louis Gresset (uncertain date, some time in 1739 or 1740).

For the next few years after the premiere of Dardanus, Rameau wrote no new operas but made minor revisions to two of his old scores for fresh performances, Hippolyte et Aricie in 1742 and Les Indes galantes in 1743. In 1744 Rameau and La Bruère returned to Dardanus, thoroughly overhauling the drama with the help of Simon-Joseph Pellegrin, who had been the librettist for Hippolyte. The final three acts were completely rewritten. The revised version has a simpler plot, fewer supernatural features and a greater focus on the emotional conflicts of the main characters. It premiered at the Paris Opéra on 23 April 1744.

The 1744 version attracted little notice until it was revived again on 15 April 1760. This time audiences acclaimed it as one of Rameau's greatest works. The cast included Sophie Arnould as Iphise. The set designs in Act 4, by René-Michel Slodtz, imitated Piranesi's famous etchings of imaginary prisons, Carceri d'invenzione. It was revived again in 1768 and 1771 with modifications to the libretto by Nicolas-René Joliveau and to the score by Pierre Montan Berton. Thereafter, it disappeared from the stage until the 20th century, although Nicolas-François Guillard reworked La Bruère's libretto for Antonio Sacchini's Dardanus in 1784.

Dardanus was produced a handful of times in the 20th century: in a concert version 1907 at the Schola Cantorum in Paris on 26 April and later the same year at the Opéra de Dijon. In 1934, it was performed in Algiers. In 1980, Raymond Leppard conducted his own hybrid version of the 1739 and 1744 scores at the Paris Opéra. Finally in 1997 and 1998, Marc Minkowski conducted a series of concert performances in Grenoble, Caen, Rennes and Lyon which formed the basis of a Deutsche Grammophon recording in 2000.