Princess Regina

You are a scientist who has invented a time machine that works by swapping bodies with people in the past. You only do it for days because the longer you are in the past, the more locked into following their time line you become. This trip there was a problem. instead of ending up in the body of the prince as planned, you ended up in the body of his sister, Princess Regina. That's not good since women at this point in history have no rights at all. Worse yet, the king has arranged a marriage between Regina and a duke who, while an important ally, is also know as a very dominant man who prefers docile women. You just hope nothing goes wrong in the 21st century, or you could be trapped as a woman in this one.