(The). A ballad in Scott's Border Minstrelsy. Lord William steals away Lady Margaret Douglas, but is pursued by her father and two brothers. Being overtaken, a fight ensues, in which the father and his two sons are sore wounded. Lord William, wounded, creeps to his mother's house, and there dies; the lady before sunrise next morning dies also.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Douglas Tragedy from Infoplease: