They aren't really famous. I'd say that they are little to well-known historic personalities with more or less information about them. (Maybe two or three biographies.) I was even 'chosen' by a historic person, when I requested someone else. It really depends on the individual. They are still just regular humans.
I once asked one of them, what they thought about having a 20-year-old girl requesting a binding of them. They haven't expected this.
