Jim,
TCM is just about my favourite ballad in its more recent forms. In its earliest known form, the 17thc broadside 'The Duke's Daughter's Cruelty' it is to me a typical warning to upper class young maids to avoid liaisons with family servants, as you say, in this case a cleric. There is absolutely no reason or evidence to suggest that the ballad is any older than this broadside version which contains all of the verses other than those borrowed in Scotland from Child 21 The Maid and the Palmer. Some of the style and language has been borrowed from oral tradition, but wasn't that ever the case?

Steve