At girl scouts I learned a story that told what the song was about, it might help you w/ the origins. It's kinda long though....

Rose awas a girl whose mother had died when she was very young. Rose lived w/ her father. She had a brave and handsome cousin who was her age. They fell deeply in love and were secretly engaged. However, before they married, both her cousin and her father went off to fight in the Crusades (it could easily have been a different war, though) and Rose went to live with a greedy uncle. During the course of the war, Rose's father was killed and her cousin was mortally wounded, making Rose's uncle her gaurdian. When she learned of the death of her fiancee, Rose's heart was completely broken. Her uncle decided to marry Rose to an old rich man so that he would have access to the money. Rose tried to refuse to obey her uncle but finally she agreed. After she was married, Rose continued to pine for her lost love and father. She was ill-treated by her husband and eventually died from a broken heart.