1 March 2018
A team of UK scientists have used STFC’s ISIS Neutron and Muon Source to investigate the origins of six medieval helmets, one of which belonged to the Black Prince of England, without needing to take a physical sample from the metal.
The research team, drawn from the Wallace Collection and Canterbury Cathedral, came to ISIS to investigate whether these late 15th century helmets contained tempered martensite, a steel crystalline structure, which would strongly indicate that they were made in the Imperial workshop at Innsbruck.
If the team at ISIS could prove that the helmets were created in Innsbruck, then that would have significant implications from both a scientific and conservation point of view. Were these incredible pieces of medieval metallurgy hand-crafted to be worn in battle or were they simply destined to be ostentatious ornaments, symbolizing both power and status?
The INES instrument at ISIS, developed to study the structure of materials and in particular cultural artefacts, was used by the scientists to measure the composition and structure at a microscopic scale without causing any damage to the helmets themselves.
One of the helmets under investigation was examined in 7 places, revealing that heat treatment had been applied to increase its hardness, presumably for battle. The low carbon content of the helmet meant that martensite had not formed but a microstructure of bainite guaranteed a higher hardness than standard steel, with the same composition. Therefore, an effort was made to harden it, suggesting its origin as Innsbruck.
“INES offers very good spatial resolution especially in backscattering, enough space to accommodate large objects, alignment facilities like lasers and a neutron camera and x-y table to scan through the samples,” explains ISIS INES instrument scientist Dr Antonella Scherillo.
Antonella Scherillo (ISIS, UK) and Francesco Grazzi (CNR, Italy) with the helm on the INES beamline.
Dr Scherillo went on to say that “Along with a selection of helmets belonging to the Wallace collection, we had the unique opportunity to examine the helmet of Prince Edward, the Black Prince, which hangs over his tomb in Canterbury Cathedral”.
“The helmet was measured in three points, and the results showed that it was manufactured using a good quality bloom, therefore it was a helm for the battlefield. Not only that but neutron diffraction revealed that the stress distribution was higher in the front plate, meaning that it has been hardened by cold working or it had been struck in battle.”
The outcomes of the study will be of vital importance in future decision making regarding the ethical conservation and restoration of the Arms & Armour collection at the Wallace Collection in London. In addition it is hoped these new research findings will influence future decisions about other historical collections in the UK and beyond
Jake Gilmore, STFC Media Manager
The analysis of the Medieval Helm of the Black Prince featured on the BBC show 'BBC South Inside Out' is available to catch up on iPlayer for a limited amount of time.
Find out more about the cutting-edge science taking place at ISIS.