In Musik & Ästhetik 6 from 2002 there is an interesting article by Jan Assmann entitled “Ägypten in Verdis Aida”. Assmann describes, among others, Verdi’s emphatic wish that the set of the performance in Milan of 1872 would be the standard forever (i.e. forever).
Verdi: “The director will in no way and under no pretext allow anything to be changed to costumes, hairstyles, jewelry… everything must be meticulously executed in accordance with the sketches. These sketches, made with the utmost care and historical precision by leading artists, are the result of careful historical study”.
We have not come across this quote in any contemporary programme book to date.