[...] I have been thinking much of you all this time as I have, for the present, broken off the composition of my Nibelung dramas in order first to produce something more practicable. You may expect a new work of mine for next winter, Tristan and Isolde, for which I particularly count on your participation and co-operation. As to what I tell you, however, I would urgently beg you to preserve strict secrecy, as whatever happens I do not wish a whisper of it to reach the public as yet.
For the moment it is a pressing matter for me to see my Rienzi, which is to be put on simultaneously at Dresden and Weimar in February, produced at the better theatres too. This needs dealing with promptly [...]. A little while ago I communicated my wishes in this respect to Herr Rottmaier; as I asked him to give you my kind regards he has probably already spoken of it to you. But what particularly weighs with me in favour of Rienzi's coming on now is the hope I have of you in this most brilliant role. Tichatschek scored his greatest triumph in it. Unfortunately, however, when I formerly attempted to popularise the opera, suitable singers for the leading parts were nowhere to be found. In Hamburg with the elderly Wurda and in Berlin with that unfortunate fellow Pfister, it was impossible to get an adequate effect. [...]
Source: Letters of Richard Wagner, Vol. 1, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 346