Chaucer's poem opens with a sleepless narrator reading a book to pass the night, and the book he reads is Ovid: the story of Ceyx and Alcyone from Metamorphoses XI, of a drowned king whose wife is told of his death by a vision sent from the house of sleep. Chaucer summarises it at length and then uses it as the machinery of his own poem. The house of sleep supplies his dream, and the pattern of a survivor who has to be brought to say aloud that the person is dead is what the whole encounter with the Black Knight then enacts. He names Ovid in the text. This is not an inferred debt but a quoted one.