Neutron tomography reveals extensive modern modification in Iron Age Iranian swords

Abstract

Early Iron Age Iranian bladed weaponry plays a significant role in discussions of metallurgical development in the ancient Near East. Due to its ubiquity in museum collections, as well as co-occurrence of bronze, iron, and bimetallic forms, it figures prominently in debates about the early ironworking techniques in the late 2nd and early 1st millennia BCE. However, dispersed collections, often lacking secure archaeological context, have made comprehensive assessment difficult. One major type of bladed weaponry, the so-called split-ear pommel swords have been the subject of much discussion, particularly around the presence of an iron core identified in many examples. Neutron tomography was applied to eight swords of this type to image their inner structure, assess the manufacturing process and determine possible recent modifications—the first time this technique has been applied to bronze Iranian weaponry of any period. The objects were recovered by the Border Force after being seized on entry to the UK and will be repatriated to Iran, providing an opportunity to investigate both ancient manufacture and modern (illicit) modifications. The results reveal extensive modern modification, namely the replacement of original blades—often made of iron—with different (but probably also ancient) bronze blades, conclusively showing that “iron cores” were not a technological feature in these bronze swords, but a result of modern tampering. Widespread iron blade replacement has masked the true extent of the production of bimetallic weapons and obscured the technological choices of early ironworkers. Given the centrality of unprovenanced objects in discussions of Iranian Iron Age metallurgy, these modifications have negative consequences for efforts to map the process of iron innovation.