The second act begins with the rejoicings over the marriage of Iphigenia.  The general joy is turned to lamentation by the discovery of Agamemnon’s vow and the impending doom of Iphigenia.  Clytemnestra passionately entreats Achilles to save her daughter, which he promises to do, though Iphigenia professes herself ready to obey her father.  In the following scene Achilles meets Agamemnon, and, after a long altercation, swears to defend Iphigenia with the last drop of his blood.  He rushes off, and Agamemnon is left in anguish to weigh his love for his daughter against his dread of the angry gods, Love triumphs and he sends Areas, his attendant, to bid Clytemnestra fly with Iphigenia home to Mycenae.

In the third act the Greeks are angrily demanding their victim.  Achilles prays Iphigenia to fly with him, but she is constant to her idea of duty, and bids him a pathetic farewell.  Achilles, however, is not to be persuaded, and in an access of noble rage swears to slay the priest upon the steps of the altar rather than submit to the sacrifice of his love.  After another farewell scene with her mother Iphigenia is led off, while Clytemnestra, seeing in imagination her daughter under the knife of the priest, bursts forth into passionate blasphemy.  Achilles and his Thessalian followers rush in to save Iphigenia, and for a time the contest rages fiercely, but eighteenth-century convention steps in.  Calchas stops the combat, saying that the gods are at length appeased; Iphigenia is restored to Achilles, and the opera ends with general rejoicings.

‘Iphigenie en Aulide’ gave Gluck a finer opportunity than he had yet had.  The canvas is broader than in ‘Alceste’ or ‘Orfeo,’ and the emotions are more varied.  The human interest, too, is more evenly sustained, and the supernatural element, which played so important a part in the two earlier works, is almost entirely absent.  Nevertheless, fine as much of the music is, the restraint which Gluck exercised over himself is too plainly perceptible, and the result is that many of the scenes are stiff and frigid.  There is scarcely a trace of the delightful lyricism which rushes through ‘Paride ed Elena’ like a flood of resistless delight.  Gluck had set his ideal of perfect declamatory truth firmly before him, and he resisted every temptation to swerve into the paths of mere musical beauty.  He had not yet learnt how to combine the two styles.  He had not yet grasped the fact that in the noblest music truth and beauty are one and the same thing.

In ‘Armide,’ produced in 1777, he made another step forward.  The libretto was the same as that used by Lulli nearly a hundred years before.  The legend, already immortalised by Tasso, was strangely different from the classical stories which had hitherto inspired his greatest works.  The opening scene strikes the note of romanticism which echoes through the whole opera.  Armida, a princess deeply versed in magic arts, laments that one knight, and one only,