and exactly how?
In the backstory, there is this wizard. Who nobly sets out to find a cure for an ailing princess. After arduous treks, intensely searching, and enormous effort, he finds that something he did in search of this knowledge, of how to cure the princess, means that he is now incapable of actually using it; he does not meet the conditions needed to actually use it and cure her.
He reacts badly.
(As a sidenote: no, he could not have handed it to someone else and let him do it.)
So the question is the princess. Since this has all become legend, she has certainly paid the debt of nature and passed on. The question is whether she
- died for the want of the cure -- which raises the little question of whether this was during his great quest, or afterwards
- died as a result of his bad reaction
- survive those only to succumb to old age in due course
- fell out of the legend entirely so that no one knows. (I can have a character ask and be answered to ensure the readers know I Meant To Do That.)
If she survived, someone else must have brought the cure, which does raise the question of rivals. . . .