Between folios 31r and 66v of College of Arms MS M 9 there is a chronicle, in French and on paper, covering the Hundred Years War from Henry V's invasion of 1415 to the arrival of Joan of Arc at the siege of Orléans in May 1429. The chronicle is only known to exist in this one copy. Its incipit at the top of the first folio, in the hand of William Worcester (1415–80/85), secretary of Sir John Fastolf (1380–1459), indicates that it was written for his master in the year of his death. At 18,217 words, the chronicle is relatively short, but it has several unique features. First, it is the only known English chronicle written in French in this period. Secondly, it is characterised by lengthy lists of people, French, English and Scottish, who participated in various battles and sieges, such names being presented in list format down the page, interspersed with narrative passages. Around 700 people are mentioned, along with around 230 places. Thirdly, the coverage of the English conquest of Maine from 1424 onwards, in which Fastolf was heavily involved, is much greater than that found in any contemporary chronicle, whether English or French.

The incipit offers an excellent starting point for the study of this fascinating chronicle but immediately raises questions since Worcester made several amendments to it. In his original version, he ascribed the work to only one author, Peter Basset, an English soldier, described as fighting under Henry V, Bedford and the later commanders in France in the reign of Henry VI. But in Worcester's revisions to the incipit, as indicated below by the italicised passages, a team of authors is indicated, which further marks out this chronicle as unusual. Those added are Christopher Hanson – who also appears twice in the narrative of the chronicle – who is described as a German who had previously served Thomas Beaufort, duke of Exeter (d. 1426), and Luket Nantron, a Parisian who was described as a clerk in the service of Fastolf. Worcester also ascribed to himself a supervisory role through the expression ‘per diligenciam’.