She was rescued by Breton fishermen and returned to France.

She told her story to someone who wrote it down, and it has survived in multiple early sources.

This is the core.

It is remarkable enough without embellishment.

The embellishments that later writers added — the dramatic storms, the supernatural terrors of the “Isle of Demons,” the extended descriptions of her grief and suffering — serve to make the story more dramatic in a conventional narrative sense, but they cannot make it more remarkable than it actually is.

A woman survived two and a half years alone on a subarctic island, through multiple winters, after the deaths of everyone who was with her.