[...] It is my purpose to enlist the aid of the scattered talents of Germany in technical and in other matters in my proposed production of my Dramatic Festival of The Ring of the Nibelungs. As regards the scenic presentation, I have decided that nothing in an exalted sense worthy of the German name will be achieved if I leave the task to the ordinary routine scene painter. Accordingly, I desire to lay the sketches of true artists before the best and most efficient scene painters, thereby inciting them to finer work. With this object I have already applied to several painters of historical subjects. Recently, however, your work [...] has been very strongly recommended to me, and it appears to come very near to being the kind of thing I want. Accordingly I take the liberty of asking you, if you think it worth while, thoroughly to study my poem, The Ring of the Nibelungs, in order to make sketches for the principal scenes (indicating both the setting and the personages of the drama), from which either you, should you wish to do so, or certain picked scene painters and stage costumiers, could work. [...]
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 658