The phenomenon, however, for which we have to account is the appearance from the earliest period to which our information extends of certain quotas of knight-service, clearly arbitrary in amount, as due from those bishops and abbots who held by military service. When and how were these _quotas_ fixed? The answer is given by Matthew Paris--one of the last quarters in which one would think of looking--where we read that, in 1070, the Conqueror episcopatus quoque et abbatias omnes quae baronias tenebant, et eatenus ab omni servitute seculari libertatem habuerant, sub servitute statuit militari, inrotulans episcopatus et abbatias _pro voluntate sua_ quot milites sibi et successoribus suis hostilitatis tempore voluit a singulis exhiberi (_Historia Anglorum_, i. 13). This passage (which perhaps represents the St Albans tradition) is dismissed by Dr Stubbs as being probably 'a mistaken account of the effects of the Domesday Survey'.[227] But the Abingdon Chronicle, quite independently, gives the same explanation, and traces the _quota_ of knights to the action taken by the Crown: Quum jam regis edicto in annalibus annotarentur quot de episcopiis quotve de abbatiis ad publicam rem tuendam milites (si forte hinc quid causae propellendae contingeret) exigerentur, etc.[228] Moreover, the Ely Chronicle bears the same witness, telling us that William Rufus, at the commencement of his reign, _debitum servitium quod pater suus imposuerat_ ab ecclesiis violenter exigit.[229] It also tells us that, when undertaking his campaign against Malcolm (1072), the Conqueror jusserat tam abbatibus quam episcopis totius Angliae _debita militiae obsequia_ transmitti;[230] and it also describes how he fixed the _quota_ of knights due by an arbitrary act of will.[231] The chronicler, like Matthew Paris, lays stress upon the facts that (1) the burden was a wholly new one; (2) its incidence was determined by the royal will alone.[232] Here, perhaps, we have the clue to the (rare) clerical exemptions from the burden of military tenure, such as the abbeys of Gloucester and of Battle.[233] The beginnings of sub-infeudation consequent on the Conqueror's action are distinctly described in the cases of Abingdon and Ely, and alluded to in those of Peterborough[234] and Evesham. At the first of these, Athelelm primo quidem stipendariis in hoc utebatur. At his sopitis incursibus ... abbas mansiones possessionum ecclesiae pertinentibus inde delegavit, edicto cuique tenore parendi de suae portionis mansione.[235] At Ely, the abbot