In 2006 Bruce Campbell and Ken Bartley brought out England on the Eve of the Black Death: an Atlas of Lay Lordship, Land and Wealth, 1300–49. This magnificently detailed analysis of the rural economy in the first half of the fourteenth century used data from the manorial extents contained in IPMs to produce distribution maps and statistics of land use and land values, agriculture, estate and social structure, and other aspects of rural society. It is sometimes said that a similarly detailed analysis cannot be produced for subsequent periods of the late Middle Ages because from the middle of the fourteenth century onwards the extents contained in IPMs become ever less detailed. This is partly true – the later IPMs do indeed lack some of the detailed lists of manorial assets which are numerous before c.1350, primarily those of crops and livestock. But nevertheless they often do provide aggregate data for these assets (for example, the total areas of arable, pasture, meadow and woodland within a manor and their values per acre, or the respective total rents received from its free and customary tenants), and some use can be made of these. In some other categories they provide data nearly as full as those to be found in the pre-1350 IPMs. This paper tests the possibilities through a case study of one type of manorial asset: mills.

Mills are dealt with in Chapter 16 of the Atlas. Its 20 pages contain 24 distribution maps and eight graphs analysing the numbers and types of mills and their geographic distributions and values, broken down by power source, function, physical condition and other factors. There is not space here to attempt to duplicate every analysis featured in the Atlas, but its major aspects will be covered.

The Atlas deals with mills only in the half century before 1350. Two monographs on the milling industry have also been published which cover the later Middle Ages after 1350. Richard Holt's The Mills of Medieval England covered the entire period from Domesday Book to c.1500, while John Langdon's Mills in the Medieval Economy focused on the two and a half centuries after 1300.