I have a master git repository, and another repository, that contains code that once was just copied from the other codebase without history, but then versioned by git again.
So the second repository has a much younger history, beginning at some state that is present as one commit in the master repository.
What would be the best way to merge this mess again? I think I first need to find out at what commit the copy was made, how to do that? How to merge the repository as a new branch, but with full history then?