[...] I recently came upon an extract from Laube's now somewhat widely-known critique of my Mastersingers and allied matters. It was indeed very painful reading, and it distressed me very greatly to think that this really vicious person could still be received in my sister's house with a certain assumption, for social purposes, of impartiality as regards her brother's case. Well, it is repugnant to me to challenge you at all upon this point, and yet [I] could wish that should he, with that remarkable unconstraint of his, speak of this matter in your house, you would impose absolute silence on him with regard to myself, yes, even forbid him to mention my name. If you should need some means to enforce this, ask him whether he would like it if I were to make public the letter he wrote this year to myself and Frau von Bülow, as also the messages addressed to the latter through Charlotte von Hagen, soliciting the post of Intendant of the theatre at Munich, and accompanied by assurances of his zeal for my works and the trend of my artistic views. It is true he might accept the challenge, for he knows very well that, even with his consent, I am incapable of that kind of baseness. It is just that which gives confidence to many of those who attack me. [...]
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 634