[...] Following my publication of a definite announcement of the performance of my Dramatic Festival in Bayreuth this year, I feel it is indispensable to make sure both of your co-operation and of your punctual attendance at rehearsals according to the timetable announced to you by a binding declaration on your part, for which you will find a form to be filled in and signed overleaf.
Will you also, please, let me have again clearly in writing the amount you feel it necessary to claim for expenses, and will you also remember that if this does not exceed the sum required last year there is no need for you to do anything further in this matter. On the other hand, I have good grounds to believe that you would ensure yourself a more generous indemnity for the sacrifices you are making on my behalf even this year, if you would promise me your assistance in the two proposed repetitions of the Dramatic Festival in 1877 and 1878. In that event you would only have to give me four weeks on each occasion, while I should be in a position to devote all the takings from the three performances to the performers and assistants after subtracting running-expenses only; for the initial expenses of production would not recur. [...]
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 687