Some speculate that Sussmayr may have taken as much credit as possible. Furthermore, Sussmayr did not give credit to Eybler. Part of the unfinished work of Mozart's Requiem was performed privately in a theater as a tribute to Mozart. It is speculated that Constanze passed Sussmayr off as a student of Mozart who helped him write the score when he was ill to make Walsegg believe that the Requiem was all Mozart's work. However, there is no strong evidence to support this. Constanze even claimed that Mozart had sung some sections to Sussmayr. Many wonder which parts were written by Eybler, Sussmayr and Mozart. Many say Constanze is responsible for the confusion over who wrote what. After receiving the commission for the Requiem, he cautiously promoted the Requiem as a work by Mozart. To make sure Walsegg didn't take credit for this piece. Furthermore, he received money every time the Requiem was performed publicly. All of Constanze's claims contributed to the mystery of the Requiem. It's tricky to figure out which of his statements are completely false and which are half-truths or