"A Sight To Dream Of, Not To Tell"

Context: On a chilly, but dark, midnight in April, Christabel, beloved daughter of the baron, Sir Leoline, retires to the woods outside the castle to pray for her absent lover. She kneels at the base of a huge oak, from the other side of which comes a moan. She discovers a beautiful damsel in a white silken robe, with bare feet, lying on the ground. She is Geraldine, and later she says that she is the daughter of Sir Roland de Vaux of Tryermaine, a former friend of the baron, although the friendship has been broken up by a quarrel. Geraldine tells of being abducted by five men on white horses who will soon return to her. Christabel conducts her into the castle; the old mastiff growls in her sleep as they pass, a sound Christabel had never heard her make. In her own chamber Christabel mentions her mother and says that she wishes she were present, a sentiment echoed by Geraldine. In a moment Geraldine, apparently addressing the empty air, commands the wandering mother to be off and says that this hour is hers. Christabel disrobes for bed, as does Geraldine. As Geraldine's clothing drops from her, Christabel sees her breast and half her side, a sight to cause nightmares but impossible to be put into words:

Beneath the lamp the lady bowed,
And slowly rolled her eyes around;
Then drawing in her breath aloud,
Like one that shuddered, she unbound
The cincture from beneath her breast:
Her silken robe, and inner vest,
Dropt to her feet, and full in view,
Behold! her bosom and half her side–
A sight to dream of, not to tell!
O shield her! shield sweet Christabel!