Why weight mattered
When metal is the medium of payment, the amount you receive depends on how it is measured. Before coins, silver and other metals were exchanged by weight, so a shared unit and a trusted balance were at the heart of trade. Even after coinage appeared, coins were themselves defined by weight, and the older units went on being used.
Measurement of length, volume and area also mattered, for taxation, building and the sale of grain, oil and wine. But weights are especially important for the study of money, because they connect markets to the idea of value.
The balance and its weights
The basic tool was the equal-arm balance. Goods or metal were put in one pan, standard weights in the other. Balance scenes appear in Egyptian tomb paintings and in other art, and the Egyptian idea of judgement, in which the heart is weighed against a feather, is a symbolic version of the same device, as in the Weighing of the Heart.
Weights were often made of stone, bronze or lead, in recognisable shapes. Well-known Mesopotamian examples include weights carved as ducks, sometimes inscribed with their value and the name of the ruler who certified them. Stone weights from the Bronze Age Indus cities were small cubes of hard stone, such as chert, and seem to follow a consistent system of ratios across a wide area, which suggests a degree of standardisation, although how it was administered is not known. Sets of balance weights were also found in the Uluburun shipwreck, indicating that merchants carried their own measuring tools.
Mesopotamia: shekel, mina and talent
Mesopotamian units used base 60, matching the sexagesimal number system. The basic unit was the shekel (Akkadian shiqlu), roughly eight grams in most estimates. Sixty shekels made a mina, approximately half a kilogram, and sixty minas made a talent, around thirty kilograms. These are approximations because the exact value varied by place and period. A talent was thus a load of about the weight a strong adult could carry with effort, which fits its use for large sums of metal and for heavy goods.
Silver in these units served as the standard of value. A price might be stated as a fraction of a shekel, but payment in grain or other goods at an agreed rate was common. Merchants at Kanesh, described under Kanesh merchant colonies, recorded their profits and debts in weighed silver. In law texts such as the laws of Hammurabi, fines, wages and interest are given in the same system, and the regulation of weights was part of royal justice. Texts mention penalties for using false weights, and rulers certified standard weights.
Egypt and the Levant
Egyptian accounts commonly used the deben, a unit of weight of roughly ninety grams, divided into ten smaller units called kite or qedet. Prices in documents of the New Kingdom were often given as equivalents in deben of copper or silver, though payment was usually made in goods. This practice shows how a unit of account could exist without actual coins.
In the Levant and Mediterranean, the shekel remained a standard weight and was later used by Phoenician and Hebrew writers. Scholars debate details of the different shekel standards, and it is best to treat claims about exact modern equivalents with caution.
Greek and Roman units
Greek city-states used the talent, mina and drachma as both weights and monetary units, but different cities used different standards. In Athens a talent was typically about twenty-six kilograms. A mina was one hundred drachmas, and a talent was sixty minas, so one talent equalled six thousand drachmas. The Athenian drachma weighed a little over four grams, and the silver tetradrachm, worth four drachmas, about seventeen grams. Because they were weights first, the coin names preserved the memory of a weight of metal. Money amounts in ancient literature are therefore often in talents, which were large sums and not coins.
Rome’s basic unit was the libra, a pound of roughly 327 grams, divided into twelve unciae, from which the English “ounce” and “inch” derive. The early Roman bronze as was originally related to this weight. The Roman state later regulated weights and measures through officials, and standard weights and measures were kept in temples and markets.
Measures beyond weight
Ancient societies measured length by body-based units such as the cubit, the distance from elbow to fingertip, and the foot. These were standardised by authorities in different ways; Egyptian royal cubits, for example, were marked on rods. Capacity measures for grain and liquids were based on standard jars or bowls. In China, the Qin state is credited with unifying weights and measures across the newly united empire after 221 BCE, described in Qin standardised measures, in order to ease tax collection and trade.
Fairness, trust and the limits of standards
Standard weights made trade possible between strangers, but they depended on trust. Cheating, with light or counterfeit weights, was a recurrent problem, and many cultures condemned it in law and in religious texts. Officials known to us from Greece and Rome supervised market weights and measures, and inspectors could fine offenders.
Standards were never perfectly uniform. Variation between regions persisted, and a unit with the same name could mean different amounts in different places. This is why historians are careful when converting an ancient unit to modern ones and usually give ranges. The central point is that a system of agreed weights was the foundation on which both pre-coin silver exchange and later coinage were built.