Passage from Tennyson

You have so many correspondents well versed in lore and legend, that I am induced to beg through you for an explanation of the allusion contained in the following passage of Tennyson:— "Morn broaden'd on the borders of the dark, Ere I saw her, who clasp'd in her last trance Her murder'd father's head." It occurs in the *Dream of Fair Women*, st. 67.