Based on memory from my folk-singing days - Steve
Benbow's "Chastity Belt". The story follows the pathos
of a young lover and the object of his desires - wife
of a "cunning old Baron" who has locked his wife in a
chastity belt while he goes away to war. Sadly, as he
is returning, he "carelessly drops the key over the
side (of his ship)". The opening theme comes with the
words, "Drop down your drawbridge, I'll enter your
keep". All very suggestive!