A Possible Coin-Sorting Function for the Gallo-Roman Dodecahedron: Aperture Size-Bands in the Nouwen Corpus (1–77)

This preprint proposes a testable functional hypothesis for Gallo-Roman bronze dodecahedra: that a substantial proportion of the examples with sufficiently complete aperture measurements and informative archaeological contexts may have served as tactile coin-sorting gauges for mixed Roman coin flows, or for other small valuable objects sorted by size. The analysis focuses primarily on the metrically tractable Nouwen corpus (items 1–77), supplemented by a small number of later, context-rich cases used qualitatively rather than as part of the main quantitative dataset. The argument is based on published pairs of opposite apertures and on the identification of internal size bands within individual objects. It follows a morphological aperture-band ladder: XS (6–8 mm), S (9–12 mm), SM (13–16 mm), M (17–19 mm), ML (20–24 mm), L (25–30 mm), XL (31–35 mm), and XXL (36–40 mm). Several dodecahedra display not random diameter distributions, but recognizable steps and shelves that broadly overlap with Roman monetary size regimes, including small fractional bands, a denarius-sized medium band, a medium-large band corresponding to the proposed antoninianus shelf, and large-bronze bands. The article advances a hypothesis that is broadly consistent with the available corpus data: that a substantial part of the bronze dodecahedron tradition may have embodied an empire-wide metrological and functional framework, not as a rigid system of identical dimensions, but as a shared threshold logic capable of accommodating chronological drift and changes in prevailing coinage regimes. Under this model, regional and temporal variation in aperture sizes would not contradict standardisation; rather, it would reflect the adaptation of a common operational principle to changing monetary environments. Such operation may have involved rotating the object and selectively blocking apertures by hand or fingers, allowing different thresholds to become active in different passes. The dodecahedron may also have been moved through a mixed mass of coins, possibly in a combing motion, with different apertures temporarily blocked in successive passes so that the remaining open apertures acted as size thresholds. Particular attention is given to military sites, administrative-fiscal centres, urban nodes, coin-rich contexts, and selected cultic settings. The revised discussion also places the proposed function within the wider monetary pressures of the early third century, especially the Caracallan reform sequence of AD 212–215 and the introduction of the so-called antoninianus. The argument remains hypothetical, but it offers a mechanically plausible and historically specific explanation for the form, aperture variability, and contextual distribution of Roman dodecahedra. Atypical cases are treated separately as material, formal, weight, or metric anomalies and are interpreted as exceptions, secondary variants, or objects belonging to adjacent traditions rather than the norm of the corpus.