FABRICATION AND CIRCULATION OF MEDIEVAL ARMOR: AN ARCHAEOMETRY APPROACH

International audienceAt the end of the Middle-Ages, armor is an object both for everyday military use and a luxury attire produced in prestigious European centers of production like Milan located in the north of Italy and Nuremberg or Augsburg in the south of Germany. Even if some research works have focused on that subject nevertheless several questions concerning the nature of the material employed, the technical skills of the craftsmen (quenching and tempering, presence of second phase particles, etc), depending on their uses and their location are still unanswered. Besides, at the same period, crucial changes occurred in the iron and ferrous alloy production chain with the emergence of the new indirect process, the blast furnace and finery. It allows producing great quantities of metal at low cost. Former studies have already showed specific skills for instance in the hardening of steel or in material choice depending on the center of production(Williams, 2003). However a linkage between the kind of reduction process used to obtain the metal and the mass production of armor in military use is a question left unresolved. Furthermore, while centers of production like Milan or Nuremberg are clearly identified by historical sources, very little is known about the origins of the metal employed. A first set of armor coming from Italy Germany and France were examined following the methodology developed in NIMBE/LAPA laboratory (metallography, MEB-EDS and LA-ICP-MS analyses) (Dillmann and L'Héritier, 2007), (Disser et al., 2014). However armor’s samples contain small size of inclusions (diameter 80μm). Thus a specific methodology has been developed in order to quantify trace elements. Two different equipments have been used: an inductively coupled plasma mass spectrometer, coupled with a nanosecond laser at the CEB center in Orleans, and with a femtosecond laser at IPREM laboratory in Pau. Primary results show the nature and quality of the metal employed, and the kind of reduction process used depending on their location. Furthermore it also allows making a first comparison with existing geochemical databases in order to test hypotheses on the origin of the materials employe