[...] Here is the programme for the Tannhäuser Overture.—I have not written a programme to any Beethoven symphony except the third and the ninth.—The Faust Overture, which will shortly be published in a revised form, has an intelligible motto.—[...] Could you, do you think, busy as you are, manage to fit in the making of a pianoforte arrangement from The Rhinegold—and that without too great delay? It is still being copied out at present, but if you could set quickly to work I should be able to have the first half sent you now. Otherwise—if you find it a burden (which I shall certainly not take amiss of you) Klindworth has offered to do it and he has already played the score through to me very finely.—[...]
Source: Letters of Richard Wagner, Vol. 1, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 288