The Border Widow's Lament is Walter Scott's re-write of the traditional ballad Famous Flower of Serving Men (Child 106).
The widow of a slain knight disguises herself as as a man and gets employment as the king's manservant. She is discovered by the king who returns unexpectedly from a hunting trip. They marry and all live happily ...... etc.
Probably the most beautifully tragic of the ballads is 'Bonnie Annie' aka as 'The Banks of Green Willow'.
A woman becomes pregnant by a sailor and is smuggled on board ship, where she gives birth.
The ship is becalmed and the sailors claim that there is a sinner on board. The mother and child are discovered, thrown overboard and drowned and (in the English version) "will be buried on the Banks of Green Willow".
Jim Carroll