Of all the written records produced under Abbot John of Northwold, perhaps the most impressive is the survey of St Edmunds’ knights’ fees which he commissioned in 1300. In the course of its composition, its anonymous author undertook extensive and thorough research. He consulted Abbot Baldwin’s Feudal Book, Domesday Book, Abbot Samson’s survey, a now lost survey made by Abbot Simon of Luton and other documents in the abbey’s archives, as well as oral evidence. From the materials thus collected he composed a well-structured and extremely detailed work. He states his intentions and method in a businesslike preface:

The author next admits that he has only discovered the ‘extents or qualities (qualitates)’ of those fees which Abbot Simon or Abbot John had held in wardship, and of those described in Baldwin’s Feudal Book or in Domesday Book. He believes that his compilation will always be useful to anyone wishing to know the names of the present tenants and about their fees and services. He then describes the arrangement of his survey, which is as follows: the name of the military tenant; his fee, the number of subtenants and the location of their holdings; the service he owed; the fines raised in the king’s court for the fee; and the extent or ‘quality’ of the fee, specifically or generally as described in the Feudal Book or in Domesday. The preface ends with a list of the fines paid to Abbot Simon by fifteen of the tenants for their service for the first Welsh war (1276), and with the note: ‘Item, in the time of Abbot John many fined with him for service on account of the second Welsh war’ (1282).