I was always under the impression that she was bound in the 1700s (when New Orleans and the Ancestral Plane was created). But what specific year/decade?
So basically in the 1700s between like 1718 and 1766 because New Orleans was created in 1718 and Ysabelle (the witch believed to create the Ancestral Plane) died in 1766?
I would say somewhere after 1776 and Before Vincent lost his child. Due to the fact she was mentioned in spirit form by Vincent when Eva started practicing sacrificial magic.