definite usage would first be adopted, and knights bound by feudal
obligations to their lords receive a definite estate from them. Our
earliest information, however, on this as on most points of tenure, is
derived from the notices of ecclesiastical practice. Lanfranc, we are
told, turned the _drengs_, the rent-paying tenants of his archiepiscopal
estates, into knights for the defence of the country; he enfeoffed a
certain number of knights who performed the military service due from
the archiepiscopal barony. This had been done before the _Domesday_
survey, and almost necessarily implies that a like measure had been
taken by the lay vassals. Lanfranc likewise maintained ten knights to
answer for the military service due from the convent of Christ Church,
which made over to him, in consideration of the relief, land worth two
hundred pounds annually. The value of the knight's fee must already have
been fixed at twenty pounds a year.

In the reign of William Rufus the abbot of Ramsey obtained a charter
which exempted his monastery from the service of ten knights due from it
on festivals, substituting the obligation to furnish three knights to
perform service on the north of the Thames--a proof that the lands of
that house had not yet been divided into knights' fees. In the next
reign, we may infer--from the favor granted by the King to the knights
who defended their lands _per loricas_ (that is, by the hauberk) that
their demesne lands shall be exempt from pecuniary taxation--that the
process of definite military infeudation had largely advanced. But it
was not even yet forced on the clerical or monastic estates. When, in
1167, the abbot of Milton, in Dorset, was questioned as to the number of
knights' fees for which he had to account, he replied that all the
services due from his monastery were discharged out of the demesne; but
he added that in the reign of Henry I, during a vacancy in the abbacy,
Bishop Roger, of Salisbury, had enfeoffed two knights out of the abbey