Answer: Prima Nocte
Longshanks reinstituted the practice, saying 'The trouble with Scotland is that it's full of Scots. Perhaps the time has come to reinstitute an old custom. Grant them prima nocte: first night. When any common girl inhabiting their lands is married, our nobles shall have sexual rights to her on the night of her wedding. If we can't get them out, we'll breed them out. That should fetch just the kind of lords we want to Scotland, taxes or no taxes.'