How the Greeks got ahead: Technological aspects of manufacture of a Corinthian type hoplite bronze helzmet from Olympia

Abstract

The object of this study is a battle helmet of Corinthian type, now in the collections of The Manchester Museum. The Corinthian helmet has been called “one of the great independent achievements of early Greek technology”. It was manufactured out of a single piece of bronze, probably on a rod-anvil, and like all body-armour it was made to measure. This required exceptional skill on the part of the smith, but once discovered the design was so efficient that it was still being used in fifteenth-century Italy, more than 2000 years after its invention around 700 BC. However, by the seventeenth century the art had been lost and had to be re-invented for modern replicas. Victorious Greek cities often set up trophies of armour from the defeated as thank-offerings at temples. Like animals being sacrificed, weapons were “killed” to be offered to the other world: so helmets had their cheek-pieces and nose-guards bent back. When the sanctuary became too crowded the trophies were cleared away and buried. The Manchester helmet was most likely found at such a site, probably Olympia itself. In order to sell it, the finder - probably in the 19th century - straightened out the cheek-pieces, which cracked at the edges, but the nose-guard was either missing or snapped off altogether: in its present form it is too short and too close to the face to be practical. X-ray fluorescence has shown that the main body of the helmet is a copper-tin alloy of varying composition at different places and containing iron and lead while the nose-guard contains zinc in high abundance. This key compositional difference indicates that the nose-guard is not the genuine broken-off piece retrieved from the finding place but is a modern substitute fabricated for restoration purposes. Synchrotron XRD at glancing angle and variable wavelength on several spots on the head and the nose-guard itself shows a shift of the copper Bragg reflections which can be related to Cu-Sn or Cu-Zn percentage composition. In addition, several corrosion products are identified. Small samples of corrosion extracted from the inside of the helmet have been used to obtain powder XRD patterns. The same samples have been studied with synchrotron micro-FTIR. Neutron diffraction sampling the bronze volume at different areas has also been used to quantify the composition. Crystallographic texture data obtained on a neutron diffractometer with large angular detector coverage was used to draw conclusions about the processes used to manufacture this precious example of archaic military technology. Some other interesting questions remain to be investigated in the near future.