Hi; I would say your topic is far too broad. Also,research implies a question. Perhaps you should pare things down to the doable by asking a question you would like to answer, such as "How often are the ballads based on truth. Ot "what perventage of the victims are women"..etc.
One of the commonest mistakes made by students doing research is to choose a topic that is huge. Listen to loads of ballads, look for common themes or areas that interest you, then research that aspect. I think you will find the job more manageable that way. Anyway, just a suggestion based on much experience doing research.