1178 weights and measures: Europe Bronze steelyard with lead weights from Roman Britain, first to second century c.e.; such weights were used by shopkeepers and traders (© The Trustees of the British Museum) Some historians argue that the standards of weights and measures used in ancient Europe, as well as around the Mediterranean Sea and among the Slavic peoples of eastern Europe and Russia, all descended from a common root system, probably that of the ancient Babylonians Thus, as people spread northward and westward throughout Europe, they based their system of weights and measures on an earlier one Historians base their argument on sophisticated mathematical analysis that shows that these systems often had common arithmetical factors Mathematicians refer to the science of weights and measures as metrology, and an important component of metrology is the notion that a particular unit of measurement is divisible into smaller units or can be multiplied into larger units Ancient Europeans may have developed different standards of measurement, but those standards were convertible into the standards used by other cultures in much the same way that, for example, American dollars can be converted into Japanese yen according to an agreed-on exchange rate Without common arithmetical factors, it would have been nearly impossible for far-flung communities to engage in trade or determine the value of gold and silver coins Many of the measurement units known to us from historical accounts in medieval Europe probably had their roots deep in antiquity In Europe, as elsewhere in the ancient world, early units of measurement typically had some relationship with the physical world The ancient Europeans started with the human body, using such standards as hand spans, the width of a fi nger, the length from the elbow to the tips of the fi ngers, and the length of a foot to measure linear distance In this regard, their units of length were little different from those of the ancient Egyptians and Babylonians Thus, for example, the ancient Irish had a unit of measure called the troigid, which was the length of a man’s foot, so a troigid was a “foot.” A troigid was made up of 12 ordlochs, or inches, with ordloch being the width of a man’s thumb Sometimes objects were used The Germans measured length by the ell, which was the length of a bolt of cloth Also commonly used to measure distance was the stride The Romans, for example, used the pace of a marching soldier, based on two consecutive positions where the right foot landed, to measure a Roman mile, which consisted of a thousand paces This measurement was imposed throughout the empire, and it remains fairly close to the British mile that survives in modern life Evidence also suggests that ancient peoples had a fairly accurate understanding of such large measurements as the circumference of the earth and the distance between the poles These measures were then broken down to provide smaller units of measurement that were used, for example, in determining the length and width of monumental buildings Again, the ancient Europeans inherited some of these systems by a process that historians not fully understand To measure weight, the ancient Europeans used the materials that surrounded them In the British Isles, for example, the stone, or 14 pounds, is still commonly used to measure a person’s weight, though in the past the stone was probably more like 16 pounds Further, agricultural commodities, often the basis of trade, were used to determine weights Throughout the ancient world people were able to develop growing, stable civilizations because of a major staple crop In Asia the crop was rice In the Americas it was maize, or corn In Europe and around the Mediterranean wheat was the staple crop, so grains of wheat were often used to form a common standard of weight Thus, for example, the weight of a certain number of grains of wheat equaled a certain measure of silver; in turn, these measures were used to determine such measures as the ounce, from the Latin word uncia This system is preserved in modern medicine, where pharmaceuticals are still often measured in grains, as well as in modern measurements of precious metals The carob seed was often used to measure silver and gold, giving rise to the modern word carat Grains of wheat were also used to measure length Again, in ancient Ireland measurements based on wheat ran as follows: The length of three grains of wheat equaled ordloch,