It is clear that by the time of the Norman Conquest in 1066 mills were regarded as important manorial assets. No manor was properly equipped unless it had a mill. This is demonstrated by the 6000 plus recorded in Domesday Book, the result of the survey undertaken in 1086 on the orders of King William which, according to the Anglo-Saxon Chronicle, set out ‘to find out what or how much each landholder had in land and livestock and what it was worth’. At this time mills would have been water- or animal-powered, the earliest written record of a windmill in England dating from about a century later.
Considering the number of mills recorded in Domesday Book it is perhaps surprising that the remains of so few medieval watermills have been found through excavation.
However, excavations on the sites of St Giles Mill and Minster Mill in Reading (above), for example, demonstrated that subsequent rebuilding had removed much of the evidence for earlier mills. At the site of the Town Mill, Droitwich, Worcestershire, some medieval foundation timbers were identified, although the position of the waterwheel pit had been subsequently moved and in a later phase (five main mill construction phases were apparent) the wheelpit was rebuilt in stone.
Watermill sites are often both multi-period and multi-phase, which can make their interpretation complex. This is also borne out by written sources. The accounts for rebuilding a mill at Kingsland, Herefordshire in the late 14th century, for example, include the cost of carting away the old timber and clearing out the foundations. Such evidence as has been found, including illustrations, shows that later medieval watermills were generally small buildings containing a single pair of millstones driven by a vertical waterwheel. It is possible, however, that horizontal-wheeled watermills continued in use in geographically remote areas, serving farms and small rural communities, much as they continued to do in the Northern and Western Isles of Scotland into the 20th century.
In order to increase capacity, and provided there was an adequate water supply, a second and sometimes a third mill might be added and the description 'two mills under one roof' is sometimes found in documentary sources. Fountains Abbey mill, North Yorkshire is an important and impressive early example of the latter.
The earliest written references which specifically mention windmills date from the 1180s. In a well-documented case of 1191 Abbot Samson of Bury St Edmunds ordered the destruction of a windmill which had been built on glebe land without his permission by Herbert the dean. References to windmills - molendina ad ventum - occur more frequently and more widespread from then on, such as at Dunwich and Willingham near Beccles, Suffolk in 1199 and 1202 respectively, at Grimsby, Lincolnshire in 1201, Henham in Essex in 1202, and at Leighton Buzzard, Bedfordshire in 1212.
Later in the 13th century windmills are recorded in the south-west of England, in Somerset in the 1220s and at Woodbury, Devon in 1289.
By the early 14th century windmills had also appeared in the north-west, at Upton-in-Widnes, Lancashire and Haulton, Cheshire, for example. While it has been suggested that windmills were built by manorial lords to supplement rather than supplant watermills, in some areas where water supply was intermittent or the topography less favourable to providing a good fall of water, windmills became a common sight in the late medieval landscape.
The earliest windmills were timber-built post mills, the whole body (sometimes called the buck) of the mill, which contained the millstones and gearing, being turned to face the sails into the wind on the top of a massive central post. For increased stability, the timbers that supported the post were often buried in the raised mound; the remains of such substructures have been found at a number of sites including Sandon Mount, Hertfordshire and near Bridgwater, Somerset.
Stone tower mills were built from at least the end of the 13th century, for example within the outer bailey of Dover castle, but stone-built mills generally appear to have been status symbols. The dominance of carpenters in the construction of medieval buildings, including mills, meant that stone structures were costly alternatives to timber-built mills. Interestingly most illustrations of windmills in medieval manuscripts show post mills, although tower mills are depicted on a small number of later medieval church wall paintings and stained glass windows. These show short, squat towers with conical caps which were turned by a tailpole to face the sails into the wind. A possible early stone tower survives at Fowey, Cornwall, which may be the windmill mentioned there in 1296, there being little evidence in the county for timber-built post mills.
Medieval windmills usually had four cloth-set sails and a single pair of millstones, over-driven from a head wheel on the windshaft. It is likely that early windmills were slowed or stopped by turning them out of the wind; it is not until the early 16th century that there is written evidence of a brake being applied to the circumference of the head wheel on the windshaft.
From documentary evidence it appears that animal-powered mills were never as numerous as water or windmills. Nevertheless they were a useful, indeed sometimes long-term alternative, convenient in towns and castles and, it seems, particularly suitable for grinding malt for brewing. A windmill on Glastonbury Abbey’s estate at Westonzoyland, Somerset, for example, was replaced by a horse mill in c.1274. Although a new windmill was built in 1316 the horse mill was retained for grinding malt until at least 1335. At St Albans Abbey in the 13th century Abbot John had a horse mill constructed next to the brewery as the watermill there was starved of water.
The number of horse mills appears to have increased in the wake of the Black Death in the late 1340s, which left more than a third of the population dead. They were cheaper and easier to build and maintain than wind or watermills, although fodder for the horses was more costly than water or wind. Not all the horse mills were legal, however: in 1455, John Chertsey set one up in Watford, the stones of which were soon seized by the Abbot of St Albans' bailiff.
All mills were an important source of income in the medieval period. This is particularly highlighted by documents that refer to soke or suit of mill, that is, the right claimed by a lord through a mill for grinding all the corn which was used within his manor. This right was a privilege rather than statutory law and not all tenants were compelled to use the lord's mill, but the income from multure, that is the toll taken by the miller, was generally a profitable one and so suit of mill was often vigorously enforced.
The gift of milling privileges, such as from one landholder to another or to a religious house, was also of importance. Grinding custom was often jealously guarded and fines were levied on those customary tenants who took their grist to other than the manorial mill or ground their corn at home, but some tenants chose to pay a fine, in order to use their own or an alternative mill. In the 13th century four handmills were confiscated at a single court sitting by St Albans Abbey, Hertfordshire, and on Chalgrave manor in Bedfordshire, Richard of Sharnbrook and Alice, daughter of William Brid, were fined 6d and 3d respectively in 1290 for not doing suit at the lord’s mill. In Chester, confirmation of the customs of the King’s Mills by Edward II in 1356 stated that ‘no one in the said city shall have handmills to the prejudice of the said mills’. John Fitzherbert, writing in the 1520s, states that it was the custom of tenants to grind corn that was grown on the lord's ground at the lord's mill, but that if corn was bought at market or elsewhere, the tenant was at liberty to grind 'where he may be best served.' He also commented that there were many differences with taking toll 'but doubt ye not, the mylner wyll be no losers.'
The term 'grist', meaning grain brought to a mill for grinding, is frequently used to describe corn mills and payment for the service provided by the miller was by toll, an amount taken in kind from each person's grain. In the 13th century the so-called Statute of Bakers stated that toll should be taken according to the communal custom of the kingdom, using measures as set by the King, and according to the strength of the watercourse, either at one twentieth or one twenty-fourth part of the grain brought for milling.
In fact the proportion of grain taken by the miller varied with both time and location, from as little as one thirtieth to as much as one tenth, with higher tolls tending to be taken in the north of England. The importance of mills to the manorial economy is graphically illustrated in the early 14th century Luttrell Psalter, which depicts both a post mill and a watermill. A prominent feature of the watermill is its stout door with a lock and sitting on the tailpole of the windmill is a large guard dog with a spiked collar.
Milling was one of the main economic activities of the later Middle Ages, becoming an important and competitive service industry that extended beyond manorial and estate boundaries. As well as timber for construction purposes, millstones were sometimes brought considerable distances, by water and land, and were the most costly single items listed in mill building and repair accounts. Cheaper stones came from local sources, such as Millstone Grit in the north and east midlands and sandstone conglomerates and greensand in the south and west. Granite was also exploited in the south-west peninsula. More expensive lava stones were imported from Germany, as they had been since Roman times, particularly into east coast ports such as King's Lynn, and there are documentary references to the acquisition of mola francisca (French millstones) for the Bishop of Winchester’s mills at Taunton, Somerset in the 13th and 14th centuries.
Mill numbers reached a peak in the early 14th century, with an estimated 10,000 watermills and windmills in England. Yet it seems this number was not sustainable and a decrease in the number of mills was already apparent before the onset of the Black Death in the 1340s. This was probably due to the period of agricultural decline that began in the latter part of the 13th century brought about by climatic change which resulted in a series of poor harvests, as well as social and economic pressures. It would take some 200 years for numbers to recover.
Farmer, D.L. 1992: Millstones for Medieval Manors, Agricultural History Review, 40.2, 97-111