It is difficult to understand how the writer can have erred so grievously, for it was fully recognised by Dr. Stubbs and by myself (‘Feudal England,’ pp. 237–239) that 1135 was the dividing point.[134] It may be as well to impress on antiquaries that fees “de antiquo feoffamento” were fees which had been in existence in 1135, at the death of Henry I., just as tenures, in Domesday Book, ‘T.R.E.,’ were those which had existed in 1066, at the death of Edward; for with these two formulas they will frequently meet. It is the “servitium debitum,” not the “antiquum feoffamentum,” which “runs back,” as Mr. Oman expresses it, to the Conquest. The result of his confusion is that his account of the origins (in England) of knight service is not only gravely erroneous, but curiously topsy-turvy. This is scarcely wonderful when we find on page 365 that he is hopelessly confused about knights and serjeants, not having grasped the elementary distinction between tenure by serjeanty and tenure by knight service. From what I have seen of the author’s account of the battle of Bannockburn, his errors, I imagine, are by no means restricted to the subjects I have here discussed. A curious combination of confidence and unwillingness to admit his mistakes, with a haste or confusion of thought that leads him into grievous error, is responsible, it would seem, for those misconceptions which render untrustworthy, as it stands, his ‘History of the Art of War.’ IV The Origin of the Exchequer