 Over the medieval period, monasteries and priories continually sought papal exemptions, so as to appropriate the glebe and tithe income of rectoral benefices in their possession to their own use.However, from the 13th century onwards, English diocesan bishops successfully established the principle that only the glebe and 'greater tithes' of grain, hay and wood could be appropriated by monastic patrons in this manner; the 'lesser tithes' had to remain within the parochial benefice; the incumbent of which thenceforward carried the title of 'vicar'.By 1535, of 8,838 rectories, 3,307 had thus been appropriated with vicarages; but at this late date, a small sub-set of vicarages in monastic ownership were not being served by beneficed clergy at all.