[...] Liszt has made the new year begin sadly for me. He had a letter from me, aimed solely against Dingelstedt, but, apart from that, couched in a certain humour which my friends for the most part know and understand; but he misunderstood it and answered it in an injured fashion so that I—and Karl who knows the circumstances—could not for a long time contain our amazement. I did all I could to help him to a belated comprehension of my letter, for I sincerely desired to free him from the madness which led him to suppose that I mocked him and his delight in Tristan. He has not answered yet; I should be sorry if pride holds him back from admitting at once that at a critical moment he allowed himself to be grievously deceived into misunderstanding a friend. I do not doubt for a moment that he will see the truth, and feel certain that his friendship will last, although I cannot help wishing for a cure of the evil from which our friendship obviously suffers—that is, lack of personal contact and intercourse. Now I realise more than ever that I must not let myself go entirely with Liszt and must exercise a certain reserve in my relations with him. He does not in the least understand my humour. [...]
I am still rather unwell and am never without ache or pain. But I am working again with eagerness. To-morrow I am sending part of the second act to Härtel's. [...] When you come to know it you will realise that in a life like mine I could only rarely and laboriously secure the appropriate hours for such work as this. I hope you will be satisfied with it. In the spring months, March, April and May, I believe I shall accomplish the third act. If only I can get interior and exterior peace I know it would not take me long. The performance is fixed tentatively for September 6th—the Grand Duke's birthday—at Karlsruhe. It is doubtful whether I shall be amnestied by then, but the Grand Duke means me to come and stay with him on his own responsibility; he asks me, however, not to let a word of this get abroad beforehand as otherwise this bold move would become impossible. I earnestly beg you to act accordingly. [...]
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 388