1      The battle took place on 10 August according to the obit for Byrhtnoth in a 12th century Ely Calendar (Library of Trinity College, Cambridge). For a comment see B. Dickins, ‘The Day of Byrhtnoth’s Death and Other Obits from a Twelfth-Century Ely Kalendar.’ Leeds Studies in English vi. (1937) pp. 14-24.
The date is given as 11 August in an early eleventh-century Winchester Calendar (British Library, Cotton MS Titus D xxvii)