The Book of the Duchess is an elegy apparently written at the request of the Duke of Lancaster, John of Gaunt concerning his first wife Blanche, who died from the plague on September 12, 1368. The dream narrative gradually moves towards the realization of Blanches death with a series of questions posed by the inquisitive dreamer. The mourning knight tells the dreamer that he blames fate for his misfortune. Typical of medieval literature, the knight feels that some larger force is to blame for his misery. Chaucers focus on fate and fortune in The Book of the Duchess should not be surprising; he relies heavily on Boethius Consolation of Philosophy in a number of his works. Boethius explains that fate is reality carried out in the course of human time. Blanches death is an example of what must come to everyone; fate, as depicted in Book of the Duchess, will inevitably turn on everyone.
The poem addresses death directly in line 479 when the knight is speaking out loud to himself,
"I have of sorwe so gret won That joye gete I never non, Now that I see my lady bryght, Which I have loved with al my myght, Is fro me ded and ys agoon. Allas, deth, what ayleth the, That thou noldest have taken me, Whan thou toke my lady swete, That was so fair, so fresh, so fre, So good, that men may wel se Of al goodnesse she had no mete!"
The knight speaks to death, an envoy to fate, not understanding why death must take Blanche his treasure away from him. The elegy has meaning to everyone who realizes that all earthly beauty must subside, but the soul which belongs to God will transcend to heaven if it receives the proper care.
After the knight and the dreamer have conversed about the knights sorrow and pain (without the dreamer exactly knowing what is ailing the knight) the knight states in line 1309 "She ys ded!" Then the poem quickly comes to an end.
The Book of the Duchess does not end with a consolatory remark, alluding to Gods divinity, the beauty of heaven, or the reward one will receive after death. One would expect to read at least several lines about the good fate of the duchess to console the knight and to reinforce the objectivity of earthly existence. Instead, the poem quickly ends forcing one to see death as the knight does, as the sudden disappearance of existence. Since Chaucer was writing about a real duchess at the request of John of Gaunt, he might have felt inclined to emphasize the knight's grief by closing with the image of the mourning knight. It would have been interesting if he had chosen to close with an image of Blanches eternal existence in heaven with God which would reinforce the notion that death is not the end of life.
 Baugh, Albert, ed. Chaucer's Major Poetry, (Englewood Cliffs, 1963), p.12.