Mills and Milling Technology
MILLS AND MILLING TECHNOLOGY
In the Roman world, water-powered mills that reduced cereal grains to either flour or meal came into use in locations as diverse as Dacia (modern day Romania), North Africa, and the province of Britannia. This relatively widespread distribution has been confirmed by recent archaeological discoveries in the territories that once formed part of the Roman Empire. Both documentary and archaeological evidence attests to their continued use in the various Barbarian kingdoms established after the empire's demise. Several early Latin vitae, or saints' lives, for example, composed in the post-Roman period, refer to the use of such mills: the lives of Orientius (c. a.d. 380–426); Romanus (c. a.d. 450); Remigius (a.d. 486–511), and Ursus (a.d. 484–507). Bishop Gregory of Tours also provides an interesting description of the construction of a monastic water mill at Loches (Indre-et-Loire) c. a.d. 500 and mentions the contemporary water mills at Dijon. In documentary sources dating from the sixth to seventh centuries a.d., many of which correspond to the orbit of the Frankish empire, there are, in total, at least sixteen references to water mills in central Europe. The law codes of the Germanic peoples provide further early documentation of the use of water-powered mills in the Barbarian world, and, not surprisingly perhaps, only the tribes that had settled within the frontiers of the Roman Empire made provisions for water mills in their law codes. These include the Pactus Alamannorum (early seventh century), the Lex Alamannorum (a.d. 717–719), and the Lex Baiwariorum (a.d. 725–728).
The development of monastic estates was perhaps the single most important factor in the spread of water-powered grain mills throughout the barbarian kingdoms prior to the tenth century. Indeed, the growth of the larger religious establishments of the Carolingian period, such as Saint-Germain-des-Prés and Lorsh, where large areas of land were brought under Benedictine control (and from which the order derived substantial profits), effectively increased the demand for mills. The Carolingian countryside, for example, had a particularly high density of mills, and the polyptych of Saint-Germain-des-Prés alone lists a staggering eighty-four mills, most of them situated on smaller streams. The increased use of water-powered mills in this period may also indicate two important developments: a growing need to ensure regular supplies of grain for a rapidly increasing rural population, and its corollary, an expansion in the cultivation of cereal crops.
Two basic types of water-powered mill were used in the barbarian kingdoms, as elsewhere in early medieval Europe, and as they still are used in the contemporary Islamic world. The first of these mills employed a horizontal waterwheel set on a vertical axle, in which one revolution of the waterwheel produced a corresponding revolution of the upper millstone (fig. 1). In the second type of water mill, the motion of a waterwheel set on a horizontal axle was communicated to a pair of millstones via wooden gearwheels set at right angles to each other (fig. 2). A large number of early medieval horizontal-wheeled mill sites have come to light in Ireland, many of which have been dated by dendrochronology to the seventh to eleventh centuries a.d. The huge corpus of Irish mill components includes almost complete mill buildings; the earliest-known examples of horizontal waterwheels; the wooden water-feeder chutes, or penstocks, associated with them; and tentering beams for adjusting the millstones. In England a well-preserved Saxon site, dated by dendrochronology to the ninth century, has been excavated at Tamworth, Staffordshire, while at Earl's Bu in the Orkney Islands the remains of a Viking Age example have come to light. In Denmark wooden structures at Omgard (c. a.d. 800) and Ljorring (c. a.d. 960) have been interpreted as the remains of horizontal-wheeled mills.
Vertical-wheeled mills dating to the seventh century have been investigated at Little Island, County Cork, Ireland, and at Old Windsor in Berkshire, England. At Little Island, a double horizontal-wheeled mill and a vertical-wheeled mill (fig. 2) operated side by side, the earliest-known close association of the two types of mill in medieval Europe. As in the case of the majority of the excavated horizontal-wheeled mills, most of the medieval vertical-wheeled mills that have come to light in Europe had substantial wooden foundations. Fragments of early medieval vertical waterwheels have also been found at Ardcloyne, County Cork, Ireland (c. a.d. 787) and at Belle-Église (c. a.d.930–980) in France. Another French site, at Audin-le-Tiche in northeastern France (c. a.d. 840–960), produced physical evidence for a vertical waterwheel with an original diameter of some 1.4 meters.
One should not forget, however, that throughout early medieval Europe simple rotary querns (from O.E. cweorn, O.H.G. quirn), which consisted of two small-diameter disk-shaped stones with a central pivot and a wooden crank handle, would still have been used in many peasant households. Indeed, querns of imported lava from the Mayern-Niedermendig area of Germany are relatively common on Middle to Late Saxon sites in England, while two lava quern blanks were recovered from the Saxon Graveney boat (Kent). During the medieval period, the simple rotary quern underwent an important technical change that made it easier to regulate the distance between the rotating upper and the stationary lower stone. The axle was extended through the base of the lower stone and allowed to pivot on an adjustable beam, which made it possible to exert greater control over the distance between the stones (a process called tentering), a factor that directly affected the coarseness of the flour or meal.
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