The Ridere of Riddles is a Scottish Saga collected by John Francis Campbell in Popular Tales of West Highlands. His fisherman/informant was named John MacKenzie who lived by Inverary.

The Ridere of Riddles

Once upon a time there lived a king who married a great lady who sadly departed during childbirth of her first son. Later the king wed another woman and she birthed a son. Both sons lads grew up strong and tall. One day the new queen had an epiphany, that her son who was the second son of the king would not inherit the king’s kingdom when he passed on. Right then she schemed a plan to poison the king’s first son.

The queen ordered the royal cooks to poison the eldest son by mixing a lethal herb into the first son’s drink. The second son overheard the queen’s conversation about poisoning the first son so…