The Book of the Duchess is an elegiac dream vision and one of the earliest of Chaucer’s major poems. It is the dominant scholarly consensus that the poem is dedicated to the memory of Blanche, the Duchess of Lancaster and first wife of a son of Edward III, John of Gaunt, and that it was written within the period of 1368 to 1372. If this is true, then the theme and discourse of melancholic solemnity in the poem maintain a profound historical resonance. Malcolm Andrew notes that “[o]ne of the manuscripts in which it survives (Bodleian Library MS Fairfax 16) contains a statement, apparently in the hand of John Stow, to the effect that The Book of the Duchess was written at the request of John of Gaunt” (…
Cummings, Raymond. "The Book of the Duchess". The Literary Encyclopedia. First published 14 December 2009; last revised 30 November -1.
[http://www.litencyc.com/php/sworks.php?rec=true&UID=1410, accessed 25 April 2015.]