Also in 1798, Constanze is noted to have given another interview to Franz Xaver Niemetschek, another biographer looking to publish a compendium of Mozart's life.
He published his biography in 1808, containing a number of claims about Mozart's receipt of the Requiem commission:
Mozart received the commission very shortly before the Coronation of Emperor Leopold II and before he received the commission to go to Prague.

He did not accept the messenger's request immediately; he wrote the commissioner and agreed to the project stating his fee but urging that he could not predict the time required to complete the work.

The same messenger appeared later, paying Mozart the sum requested plus a note promising a bonus at the work's completion.

He started composing the work upon his return from Prague.

He fell ill while writing the work
He told Constanze "I am only too conscious... my end will not be long in coming: for sure, someone has poisoned me!
I cannot rid my mind of this thought."

Constanze thought that the Requiem was overstraining him; she called the doctor and took away the score.

On the day of his death, he had the score brought to his bed.

The messenger took the unfinished Requiem soon after Mozart's death.

Constanze never learned the commissioner's name.

This account, too, has fallen under scrutiny and criticism of its accuracy.
According to letters, Constanze most certainly knew the name of the commissioner by the time this interview was released in 1800.
Additionally, the Requiem was not given to the messenger until some time after Mozart's death.
This interview contains the only account from Constanze herself of the claim that she took the Requiem away from Wolfgang for a significant duration during his composition of it.
Otherwise, the timeline provided in this account is historically probable.
Also in 1798, Constanze is noted to have given another interview to Franz Xaver Niemetschek, another biographer looking to publish a compendium of Mozart's life. He published his biography in 1808, containing a number of claims about Mozart's receipt of the Requiem commission:
Mozart received the commission very shortly before the Coronation of Emperor Leopold II and before he received the commission to go to Prague.
He did not accept the messenger's request immediately; he wrote the commissioner and agreed to the project stating his fee but urging that he could not predict the time required to complete the work.
The same messenger appeared later, paying Mozart the sum requested plus a note promising a bonus at the work's completion.
He started composing the work upon his return from Prague.
He fell ill while writing the work
He told Constanze "I am only too conscious... my end will not be long in coming: for sure, someone has poisoned me! I cannot rid my mind of this thought."
Constanze thought that the Requiem was overstraining him; she called the doctor and took away the score.
On the day of his death, he had the score brought to his bed.
The messenger took the unfinished Requiem soon after Mozart's death.
Constanze never learned the commissioner's name.
This account, too, has fallen under scrutiny and criticism of its accuracy. According to letters, Constanze most certainly knew the name of the commissioner by the time this interview was released in 1800. Additionally, the Requiem was not given to the messenger until some time after Mozart's death. This interview contains the only account from Constanze herself of the claim that she took the Requiem away from Wolfgang for a significant duration during his composition of it. Otherwise, the timeline provided in this account is historically probable.
Requiem (Mozart)