[...] I set most store by Berlin. There you could certainly hold a complete winter season successfully; only then it would be necessary to expend the utmost care upon the accuracy and excellence, the type and style, of the performances. [...]
As far as I understand, you already have one of the Berlin theatres in view. The architect Brückwald also told me that you had got him to work out the plans for a real Wagner theatre for Berlin, faithful to the Bayreuth model, and I was able to give my willing assent to the good idea of inserting a second row of boxes into the so-called Fürstengalerie [Princes' circle], and of making it possible to charge two prices in the pit by slightly raising half the seats.
I am ready to support you in this undertaking in every respect—you know that. Only I do not know how to reply to the request you have recently put to me again to be allowed to advertise the performance of Parsifal at this theatre, after I have already given you my most definite answer on that point. Parsifal must belong exclusively to my own Bayreuth creation, and my Dramatic Festival Theatre there will be used exclusively for producing this one work for a given season year after year. This isolation is demanded by the whole conception of the subject. My Bayreuth creation stands and falls with Parsifal. It will pass away, indeed, at my death, for I know of no one, and can know of no one, to keep it going on my lines. If my strength (which on these occasions is put to a severe test) fail greatly before my death, so that I am unable to take part in the performances, I shall certainly have to consider means of preserving my work pure as far as possible for the world. If by then you have attained, and maintained, the right standing for your Wagner theatre by the exclusive and ever-improving production of all my earlier works, Sacred Dramatic Festivals might well be entrusted to it at certain special seasons, and to it alone. On this understanding only could I surrender my Parsifal.—You might very well discuss this confidentially, on the basis of what I have told you to-day, with persons whose help you need to found your theatre. But you would force me to take back all I have said if a word of this business were made public. You know in what a base, malicious way our journalists get hold of such news, and you cannot expect me to throw my Bayreuth creation, attained through such inexpressible effort, to be vulgarly mauled. [...]
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 736