Metrological Modifications on Iberian Weights (6th–1st c. BCE): A Computer-Based Approach

Western Europe’s ancient metrology and weighing systems are still vastly under-studied. We lack typologies for the weights, numeral systems and metrological units used during the Bronze and Iron Ages even if the existence of such material and conceptual tools are identified since at least the Late Bronze Age. Within this unchartered fieldwork, the Iberian Peninsula is the exception as our knowledge of weighing practices in this area is far more detailed than in the rest of Western Europe. There are several reasons for this situation; the first originates in the characteristics of the weight themselves. The Iberian Peninsula distinguishes itself by its use of very typical metal weights since the Late Bronze Age, with a discoidal shape and a central hole. These typical shapes helped to identify these objects in archaeological contexts since 1930 in the Iberian Levantine area. Since then, a constant stream of publications have progressively augmented this corpus until the turn of the 21st c. which has helped us reconstruct the array of weighing tools used during the Iberian Period (6th–1st c. BCE) in the Iberian Levantine area. Even if we have less research results for the rest of the Peninsula, this practice is attested throughout the entire area. Iberian weighing practices appear to be a relatively homogenous phenomenon over a long time period. Metrology in this context is more problematic, as dis-cussed below, and the current state of research hardly addresses the unit(s) and metrological system(s) that were used. Rather than broach this problematic topic, this paper focuses on a phenomenon observed between the 4th and the 1st c. BCE, whereby the mass of certain weights is modified by adding or withdrawing metal. This paper aims to deal with this practice using new methods in order to assess the impact of such transfor-mations on the mass of scale weights and, consequently, on their functionality.