Discussing the Prelude, William Foster Apthorp wrote:
"Like the hero's career in the opera, it begins, as it were, in the clouds, then gradually descends farther and farther until it embraces all the lower tones of the orchestra, and then returns to the clouds again. Its single theme is developed in free polyphony by various successive groups of instruments, each of which groups proceeds with free counter-thematic work as the next group enters with the theme. First we have the violins _piano_ in their higher registers; then come the flutes, oboes, and clarinets; then the violas, 'cellos, horns, bassoons, and double-basses; lastly the trumpets, trombones, and the tuba _fortissimo_; then comes the _decrescendo_, ending _pianissimo_ in the high violins and flutes."
The composer, who could descant with the best of them, paraded his rhetorical gifts on the Prelude (the translation is by William Ashton Ellis):
"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 output 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 the 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.