The royals mentioned at the end of "The Bonny Swans" are the heroine's in-law relations, not her biological family.
- The first verse introduces a farmer in the north country with three daughters, the youngest being the tragic heroine of the story. The final verses introduce her father the king, her mother the queen, her hitherto-unmentioned brother Hugh, and William whom she describes as "sweet and true". All of this could be consistent with the first verse if the king, queen and Hugh are her in-law relations whom she refers to as her father, mother and brother respectively after she married Prince William who is son to the king and queen and brother to Hugh. Her sister Anne murdered her out of jealousy and then managed to woo and marry the widowed William, or alternatively, perhaps it was the custom of the land for a widowed prince to marry his dead wife's sister, and she took advantage of this custom to supplant the heroine. Perhaps the never-mentioned-again middle sister from the first verse similarly married Hugh before the start of the story, and the fact that there was no third brother for Anne fuelled the latter's murderous jealousy (rather like the wicked older sister Roussette from Princess Belle-Etoile).
- In the second verse, the drowning sister tells her attacker, "Oh sister, oh sister, pray lend me your hand...and I will give you house and land." It's unlikely a young woman in medieval times would independently have land or other resources to dole out...unless she'd married into royalty.
- There was an interview in which McKennitt spoke of the song having multiple versions throughout history, and she specifically mentioned the oddity of the heroine having farming parents at the start and royal ones at the end possibly being an artifact of this, or just general shifting and changing over time thanks to how the oral tradition works. But the above analysis is a very sensible and intriguing way to reconcile the discrepancy!
