Answer: Romeo is a Montague and Juliet is a Capulet. They are a part of two families that have a long-lasting feud against each other that seems like it will never end. Romeo and Juliet were not able to be together because of their families, but they still made it happen.
Well, there are two answers to this question actually.
I believe that a medieval ballad would definitely please a Romantic poet, because it is all about love and all that.
However, in Romanticism, poets and writers were obsessed with the macabre, so they would probably enjoy Greek tragedies as well.