Dear Herr Voltz!
Try this one: for the performing rights of Iphigenia, nothing at all, but royalties from my older operas.
Or else—demand for Iphigenia what you think appropriate; I suggest a heavy fee, for that opera will hardly be given often.
Best regards,
Richard Wagner
Source: Letters of Richard Wagner: The Burrell Collection, ed. John N. Burk (Macmillan, 1950), No. 324