Wagner’s own explanation has been translated into English as follows:
“Love seemed to have vanished from a world of hatred and quarreling; as a lawgiver she was no longer to be found among the communities of men. Emancipating itself from barren care for gain and possession, the sole arbiter of all worldly intercourse, the human heart’s unquenchable love-longing again at length craved to appease a want, which, the more warmly and intensely it made itself felt under the pressure of reality, was the less easy to satisfy, on account of this very reality. It was beyond the confines of the actual world that man’s ecstatic imaginative power fixed the source as well as the outflow of this incomprehensible impulse of love, and from the desire of a comforting sensuous conception of this supersensuous idea invested it with a wonderful form, which, under the name of the ‘Holy Grail,’ though conceived as actually existing, yet unapproachably far off, was believed in, longed for, and sought for. The Holy Grail was the costly vessel out of which, at the Last Supper, our Saviour drank with His disciples, and in which His blood was received when out of love for His brethren He suffered upon a cross, and which till this day has been preserved with lively zeal as the source of undying love; albeit, at one time this cup of salvation was taken away from unworthy mankind, but at length was brought back again from the heights of heaven by a band of angels, and delivered into the keeping of fervently loving, solitary men, who, wondrously strengthened and blessed by its presence, and purified in heart, were consecrated as the earthly champions of eternal love.
“This miraculous delivery of the Holy Grail, escorted by an angelic host, and the handing of it over into the custody of highly favored men, was selected by the author of Lohengrin, a knight of the Grail, for the introduction of his drama, as the subject to be musically portrayed; just as here, for the sake of explanation, he may be allowed to bring it forward as an object for the mental receptive power of his hearers.
“The prelude is scored for three flutes, two oboes, English horn, two clarinets, bass clarinet, four horns, three trumpets, three trombones, bass tuba, kettledrums, cymbals, and strings.”
PRELUDE AND LIEBESTOD FROM “TRISTAN UND ISOLDE”
The subject of Tristan und Isolde was first mentioned by Wagner in a letter to Liszt in the latter part of 1854; the poem was written at Zürich in the summer of 1857, and finished in September of that year. The composition of the first act was completed at Zürich, December 31, 1857 (some say, but only in the sketch); the second act was completed at Venice in March, 1859; the third act at Lucerne in August, 1859.
Wagner himself frequently conducted the prelude and Love-Death, arranged by him for orchestra alone, in the concerts given by him in 1863. At those given in Carlsruhe and Löwenberg the programme characterized the prelude as Liebestod and the latter section, now known as Liebestod, as Verklärung (Transfiguration).
The prelude, langsam und schmachtend (slow and languishingly), in A minor, 6-8, is a gradual and long-continued crescendo to a most sonorous fortissimo; a shorter decrescendo leads back to pianissimo. It is free in form and of continuous development. There are two chief themes: the first phrase, sung by violoncellos, is combined in the third measure with a phrase ascending chromatically and given to the oboes.
These phrases form a theme known as the “Love Potion” motive, or the motive of “Longing”; for passionate commentators are not yet agreed about the terminology. The second theme, again sung by the violoncellos, a voluptuous theme, is entitled “Tristan’s Love Glance.”
The prelude is scored for three flutes (and piccolo), two oboes, English horn, two clarinets, bass clarinet, three bassoons, four horns, three trumpets, three trombones, bass tuba, kettledrums, harp, and the usual strings.