Exploring the chemical composition and corrosion patterns of arrowheads used in the Siege of Motya (397 BC) through a multi-analytical approach

Abstract

• A set of arrowheads attributed to the siege of Motya are studied. • X-ray maps showed a complex zoning of the elements. • SEM and EMPA showed the occurrence of Cu-Sn alloys and leaded bronzes. • Liesegang phenomenon is recognized in conical shaped arrowhead. • Copper trihydroxichlorides are identified in all arrowheads. This study examines a set of bronze arrowheads involved in the Siege of Motya (Italy) and aims to determine their microstructures, corrosion patterns and production techniques using Scanning Electron Microscope, X-ray maps, Electron Microprobe Analysis and X-ray diffraction. The arrowheads characterized by plane and conical shapes are made from Cu-Sn-alloy, featuring Liesegang rings with streaks of Sn-oxide interposed between Cu 2 O and Cu 2 (OH) 3 Cl layers. Those of pyramidal or lanceolate shapes are made from Cu-Pb-Sn alloy and contain different corrosive products triggered by exposure to high levels of chloride-rich conditions. These results have highlighted an interesting correlation between alloy microstructures, compositions, typology and geographic provenance, and thus provide new insight on the weaponry and poliorcetics of the Syracusan army that led to the defeat of Motya in 397/6 BC.