Synopsis
A great king had a daughter (Lady Diamond, Daisy, Dysmal, or Dysie), who fell in love with his kitchen boy. She became pregnant. Her father demands to know the boy, and she tells him. He has the kitchen boy secretly murdered, but then, in most variants, brings his heart to his daughter. She dies. In most variants, the king laments the deaths.
Variants
The story is derived from that of Ghismonda and Guiscardo from The Decameron of Giovanni Boccaccio.
Steeleye Span recorded a version on their 1986 album Back in Line.
The 2011 debut album by Bryony Griffith & Will Hampson of The Demon Barbers is entitled "Lady Diamond" and features a recording of the ballad.
References
Lady Diamond Wikipedia(Text) CC BY-SA