The Chronica Maiora of Thomas Walsingham [1376-1422]

Thomas of Walsingham was a monk in the abbey of St Albans, then the equivalent of the National Archives where all official documents were deposited about the war. 

Based on the reports, letters, charters, and reports of parliamentary debates that Thomas was able to access, he wrote a history from 1376 until the year that he died, 1422, so the work is an account of the war as it appeared to an educated contemporary.