The desirability of possessing unencumbered "bookland" in preference to "folkland" must have been immediately apparent to the laity, as Bede complained in a letter to Archbishop Ecgbert of York in 731, regarding the vast tracts of land acquired by "pretended monks" whose licentious interests were anything but Christian. To begin with, church land under bookright was exempt from taxation and immune from the "trimodia necessitas", that is, the upkeep of bridges and fortifications on the land, and the provision of military service, or fyrd. These immunities were removed from church land by the end of the 8th century, perhaps in response to the situation of which Bede complains.