Like many composers of his generation, the career of Christoph Willibald Gluck (1714- 1787) was centred on music-theatre - the ballet and especially opera. His earliest operas were written for Milan and Venice, before a visit to London in 1746 where he produced two new operas and met Handel, to whom he developed a lifelong veneration, as well as the reforming actor David Garrick. From 1748 he was working at Vienna, and it was during his residency there in the following decade that he began to move away from the accepted conventions of opera seria, in which the dramatic narrative unfolds through recitative, alternating with lengthy and often florid da capo arias. His collaboration with the colourful Italian poet Raniero de’ Calzabigi, sometime murderer and friend of Casonova, decisively encouraged his own inclinations to a new and more fluent concept of dramatic art, 'restricting music to its true purpose of expressing the poetry and reinforcing the dramatic situation, without interrupting the action or hampering it with superfluous embellishments'. Their reforming ideas came to full fruition in Orfeo ed Euridice (1762), Alceste (1766-7), and Paride ed Elena (1770), the first of which became recognised as one of the great turning points in operatic development.

Orfeo sets a familiar Greek myth, related by Virgil and Ovid, which had already provided inspiration for numerous pastorali and opere, including seminal works by Poliziano and Germi (1472) and by Rinuccini and Peri (1600). The character of Orpheus, variously portrayed as poet, singer and lutenist, and the story of the enduring power of his love for Euridice, held a considerable natural appeal to writers and musicians of all ages, although subject to many variations of emphasis and narrative. Calzabigi's presentation of the story is succinct and focused, rejecting the proliferation of divinities (with the exception of Amor) who feature in most other versions, ignoring any sub-plot, and compressing the narrative into effectively a single unbroken passage of time. Although neither of the main protagonists is granted any sense of individual personality, nevertheless the human emotions expressed, especially in the tragic and tortuous journey out of Hades, are clear and eternally true. The confusion and fear of Euridice as she is led away from the security of Elysium and Orpheus' frustration at maintaining the divine injunction imposed upon him are precisely and deeply conveyed, both in the words and Gluck's setting of them. Only the ending has caused grief to many 20th- century critics and producers, even to the extent of drastic tampering with the score. In his own ouiline of the plot, the librettist explains how ‘in order to adapt the story to the stage, I have had to modify the tragic ending’: thus, the dénouement of the legend in which Orpheus loses his wife irrevocably, is replaced by a happy ending in accordance with 18th-century expectations. However, might we not echo tonight the reviewer of the first performance who commented that ‘all spectators, who otherwise would have returned to their homes saddened by shared suffering, are most grateful to him for this happy change’?

The mastery of Gluck's score derives from its intense lyricism, its simplicity, and its powerful evocation of mood and emotion. Most significant in the musicological sense is the linking of a number of short recitatives, arias, choruses, and ballet-interludes, so that the music flows through uninterrupted sequences of varying and yet related passages. Each of the main dramatic scenes thus has a continuity and independence which was later to be admired and imitated by the great romantics, Berlioz and Wagner. A bold architecture in the scenes individually and in the opera as a whole provides a monumentality and breadth far in excess of its relatively brief duration.

Gluck effectively composed the opera twice. The first performance at the Burgtheater in Vienna on October 5th, 1762, used the Italian libretto of Calzabigi with Orpheus sung by the renowned contralto castrato singer Guadagni. In 1774 the score was completely revised for a resoundingly successful production at the Académie Royale, Paris, sung in a French translation, with the title-rôle rewritten for the high tenor Joseph le Gros. This newly-orchestrated version was substantially longer, with additional arias and ballet movements, marvellous music in themselves but which nevertheless compromise the architecture and refinement of the original. A further rewriting, in effect an amalgamation of the two scores, was made by Berlioz in 1859 for performance in Paris by the mezzo-soprano Pauline Viardot-Garcia, and this edition remained in general use until the authentic performance movement of the past two decades. Tonight's performance adheres to the original Vienna version, although in a reduced orchestration and with the omission of the sequence of ballets from the final scene.