I'm working on a medieval fantasy piece and, although it is fantasy, I'd like to have some proper base knowledge of medieval times. I know a few basic key things that will suit me just fine, but I have a question about royalty. Correct me if I'm wrong, but families typically got married amongst nations as signs for an alliance correct? Well lets say a prince marries a girl, she becomes a princess, and then the prince dies. What happens to the princess? Also on a side note, does a princess/queen take the last name of the prince/king when married?