The City of Winchester is fortunate to possess the oldest existing set of standard weights, the most ancient standard yard measure, and an impressive collection of other ancient measures and weights. These standard weights and measures were utilized to gauge the merchandise they sold, as well as the measurements employed by merchants to assess their goods, thereby supporting both government taxation and equitable trade.
Winchester Measurement
To trace the origins of the term "Winchester measurement," we must journey back to the Anglo-Saxon era when, during the rule of Alfred the Great (871-899 AD), Winchester began to assume an increasingly significant role in the administration of the kingdom and as a hub for trade. During the reign of Edgar the Peaceful (959-975 AD), it was ordained that all measurements should adhere to the standards maintained in Winchester and London. Consequently, the bushel and its subdivisions—pecks, gallons, quarts, and pints—became recognized as the "Winchester measurement" and were employed for quantifying all grain and agricultural products until their replacement by the imperial system (approximately 3% larger) in 1824. Nevertheless, the traditional Winchester bushel is still utilized in the United States.
The Troy Weight
The Troy weight stands as the oldest known English commercial weight, with its name believed to be derived from the French city of Troyes, a significant trading center during the early Middle Ages. Under this system, 1 troy pound equals 12 ounces, which further breaks down into 240 pennyweights (dwt) or 5,760 troy grains. Traditionally, a troy grain is equivalent in weight to a barley grain. The earliest weights were based on seeds, which is why the terms "grain" and "carat" are still in use today: "grain" originated from wheat grains, while "carat" stems from the seeds of the carob plant. Troy weights are now exclusively employed for precious metals and gemstones.
The Avoirdupois Weight
The Avoirdupois weight gradually developed from the Troy weight in the late 13th and early 14th centuries. Its name comes from the Old French "avoir de pois," meaning "goods of weight," reflecting the concept that the quantity of goods, rather than weight alone, was relevant in trade. In the Avoirdupois system, 1 pound equals 16 ounces, which equals 7,000 grains, and 14 pounds make up 1 stone. When referring to the imperial system, it is the Avoirdupois system that is typically mentioned.
Weight of Wool
As previously mentioned, Winchester weights and measures served as standards to verify the consistency of traded goods, and during medieval England, one of the most significant traded commodities was wool. By 1421, customs duties derived from wool alone constituted 74 percent of all customs revenue in England. Similar to the variability in the pound sterling's size, the size of the stone also fluctuated. However, in 1340, during the reign of Edward III, the stone was set at 14 pounds sterling. This alteration may have been made to align with the measurements employed in certain continental European trading centers, such as Flanders, to facilitate trade. Perhaps this change contributed to the preference for the Avoirdupois system over the Troy system. Edward III decreed that a bag of wool, defined as 2 weights, should be equivalent to 26 stones or 364 pounds.