The Symphonie fantastique was written in reaction to the intense and unreciprocated passion Berlioz felt for Harriet Smithson, and with something of the resentment he felt, possibly augmented by his brief association with Camille Moke, who was to marry the piano manufacturer Pleyel. In the end Berlioz was to marry his Ophelia, a match that brought neither of them any lasting satisfaction, as her own career waned into querulous drunkenness and his musical and extra-marital amatory preoccupations assumed greater importance.
The Symphonie fantastique is a remarkable work, autobiographical in content and immensely influential in the path it suggested to future composers, anxious to extend the scope of musical expression in the generation after Beethoven. Described as An Episode in the Life of an Artist, the symphony is haunted by an idée fixe, a recurrent fragment of melody, symbolizing the beloved, a prototype of the Leitmotiv, to be developed by Wagner. In 1830 the autobiographical nature of the symphony represented something entirely new.
A young musician, in despair, has poisoned himself with opium and in a long sleep has a series of vivid dreams and nightmares, the idea of his beloved coming again and again to his mind. He recalls the joys and depressions of the past, before she came into his life, and then the neurotic despair and jealousy that her appearance brought him, with passing consolation in religious serenity. The second movement evokes the music of a ball, at which, in the swirl of the dance, he catches glimpses of his beloved again. This is followed by a third movement that cost the composer much labour. In the countryside two shepherd boys play a melody to call the cows, and all is tranquility until the beloved appears again, with all the anxious questioning that that must provoke. A shepherd plays his pipe, but this time there is no answer, and as the sun sets distant thunder is heard, followed by silence. The March to the Scaffold, written in one night, brings a dream of the murder of the beloved, for which the hero is condemned to death. The march, with its steady tread, has its wilder moments, as the procession makes its way through the crowd. The beloved appears at the moment before the axe falls. The final movement is a Witches' Sabbath, a wild orgy of diabolic celebration, the idée fixe of the beloved now a shrill mockery. The death knell is heard and the sound of the traditional chant of the Dies irae, the hymn of the Day of Judgement from the Requiem Mass, mingles with the dance, as the work draws to an end.