Weight systems in Bronze Age markets

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES—A study* suggests that the interaction of merchants, without substantial intervention by political authorities, likely explains the diffusion of Bronze Age technology for weighing goods. Knowing the weight of a commodity provides an objective measure for valuing goods in the marketplace. To determine how different units of weight emerged in different regions, Nicola Ialongo and colleagues compared weight systems in use between Western Europe and the Indus Valley from 3000 to 1000 BCE. Analysis of 2,274 balance weights from 127 sites revealed that, with the exception of those from the Indus Valley, new units of weight that differ only slightly from each other appear in a gradual spread west of Mesopotamia. To determine if the gradual formation of these systems could be due to propagation of error from a single weight system, the authors modeled the creation of 100 new units. Taking into account factors such as instrumental error, the simulation supported a single origin between Mesopotamia and Europe and also showed that the Indus Valley likely developed an independent weight system. According to the authors, if information flow in Eurasian trade supported a common weight system, it may have also been sufficient to enable reactions to local price fluctuations.

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Stone balance weights with weight marks from the Bronze Age tell settlement of Arslantepe (Malatya, Turkey). The weights were found grouped together on the floor of a private house of phase VI D1. Missione Archeologica Italiana nell’Anatolia Orientale/Roberto Ceccacci.

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