
Summary
The Book of the Duchess, also known as The Deth of Blaunche, is the earliest of Geoffrey Chaucer's major poems, preceded only by his short poem, "An ABC", and possibly by his translation of The Romaunt of the Rose. Based on the themes and title of the poem, most sources put the date of composition after 12 September 1368 and before 1372, with many recent studies privileging a date as early as the end of 1368.
Source: Wikipedia (CC BY-SA).