In 1281, King Edward ordered Roger of Leicester (justice of Common Bench) to have an extent made of all the manors, lands and tenements held by the prior and convent of St Edmunds. An extent recorded the annual leasable value of every manor held in demesne, that is of every building and piece of land and of all labour services and rents pertaining to it. The mandate was probably issued in connection with the king’s confirmation in November 1281 of the division of portions between the abbot and convent. Abbot John and the convent had obtained the confirmation in order to prevent the crown taking over the convent’s portion as well as the abbot’s barony during future vacancies, as it had done in 1279. The king needed to know what revenue he should have had during the 1279 vacancy, and how much he lost by his undertaking that in future vacancies the convent would be left in possession of its portion. This information would have helped decide the amount which the abbey should pay as a fine for the confirmation. In the same way, an extent of the rich demesne manor of Cockfield was probably made as a result of the grant of the manor by Abbot Simon to the prior and convent in 1275. Throughout the thirteenth century the number of extents of demesnes proliferated, especially towards the end of the century. The earliest surviving ones were made for the Crown of properties which came into its hands after the death of tenants-in-chief. However, it was not long before private landlords began making extents of their demesne manors. Their purpose was to improve management and so to increase the profitability of their estates. The demesne manors were of course those which landlords exploited directly. Those estates which were leased out for fixed rents were not described in detail, since the landlord could not increase his profits from them.

A number of extents survive from St Edmunds dating from John of Northwold’s abbacy, and others no doubt existed but have been lost. However, which (if any) of the surviving ones was, or were, made in response to Edward’s mandate to Roger of Leicester is impossible to say.