In Genesis 29, Jacob intended to marry Rachel but her father substituted Leah and Jacob didn’t find out about the problem until after, uhh, going through it.
This sounds like a Canon 1097 §1 ground for annulment. Jacob didn’t intend to marry Leah, he intended to marry Rachel. In fact, one commentator used this very couple as an example of what is really involved in a 1097 section 1 nullity situation.
Was the marriage actually null? Were the requirements for a valid marriage actually different back then and mistakes of person only nullified marriages entered into after Jesus came? Is “error of person” not an eternal principle of marriage validity but a discipline that the CC could change tomorrow, deciding that from 2015 onwards there is to be a “know your fiancee” policy where one is required to personally verify that the one standing at the altar is the person you expect it to be and mistakes are your problem?
Was this a ground for nullity even in those days, and God made an exception for this one couple in this specific case?