Most Honoured Friend!
I begin by asking you to rest assured that I am deliberating over the composition of your opera [Der Gang nach dem Eisenhammer] purely out of my great interest in the many beautiful and excellent things it contains. I think your music good almost throughout. There are certain portions, such as the introduction to the first act, the whole Eisenhammer scene and so on, which I value more highly than many an entire modern opera or oratorio, for they bear the noblest stamp of Romanticism. With so much which truly enchants me, I am naturally inclined to feel that a work like this should not be withheld from the world and it is only when I fix my mind on the desirability of the actual production of the opera that I begin to wish some things other than they are. Let me be brief. I will first speak of what resides in the subject itself and is rooted in the dramatic construction of the libretto. [...] We will consider simply how the opera can be altered from its present form so as to make it a more concentrated, that is to say a more effective, music drama, without going very destructively to work. In all these proposals [...] the end I have in view is the possibility of helping your opera to a success upon the boards. First of all, your libretto contains too many characters and too many scenes. I wish you had never known Holbein's incoherent, higgledy-piggledy, insipid version and had had nothing before you but Schiller's ballad and you would have come far nearer to constructing a sound opera. [...] Listen now, while I tell you my proposal for a complete scenic rearrangement in your libretto, a proposal which I make to you upon mature consideration. [...]
[...] It is asking a lot of you to undertake such a great alteration in your work. [...] If you take my advice and undergo this difficult and painful operation I shall be very glad to think I have been able to influence you to it, for I am certain that by this means we shall all be the better of a good and successful piece of operatic work. [...]
Source: Letters of Richard Wagner, Vol. 1, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 114