Wolverine's history in the Marvel Universe can be quite convoluted. A problem with unending storytelling is that things are changed multiples times as years go by. In Wolverine's case, every time readers think they know his past, Marvel throws a curveball at them and introduces an entirely new factor at them. It's a way to keep one of the most important parts of Wolverine's appeal - the man of mystery with an opaque past. By the mid to late-00s, Wolverine fans thought they knew everything about Wolverine, but were about to learn that everything they knew wasn't exactly as it seemed.
Source：https://www.cbr.com/wolverine-romulus-history-marvel-comics/
