This project presents a study of iron technology in Early Medieval (fifth to eleventh centuries AD) Britain through the examination of iron found in settlement contexts. This is a period characterized by significant cultural, political and social changes. The effect of these changes on iron technology has never been investigated on a large scale. Previous studies on iron focused either on individual sites or on single artefact types, and did not provide any clear multi-region interpretive framework. A longstanding problem has been in identifying the extent of usage of a key alloy: phosphoric iron. This research project examined iron assemblages from eight settlement sites of varying size, culture, economic and social status from across Britain. From each settlement a mixed assemblage of iron artefacts was sampled, including edged tools, items of personal adornment, construction materials, and craft tools. Analysis was by traditional archaeometallurgical techniques alongside SEM-EDS elemental analysis. Alloy usage, specifically relating to phosphoric iron, was examined and the manufacturing techniques assessed. It was shown that elemental analysis is the only reliable method to determine the presence of phosphorus in iron and demonstrated that the traditional phosphoric indicators as observed during optical microscopy are insufficient. Results were subjected to a series of comparisons based on settlement size, the inferred social status, and cultural affinities. The results demonstrate the high technological level of iron artefact production across the country. All areas had access to the full range of iron alloys and employed a highly developed range of smithing techniques. Phosphoric iron was a prevalent alloy in this period. Based on these results, a model of the Early Medieval iron industry is generated, suggesting a vibrant economy in which both local and traded irons were significant.

After carbon, phosphorus is the most commonly detected element in archaeological iron. The typical phosphoric iron range is 0.1wt% to 1wt%P. The predominant source of phosphorus in iron is the ore smelted. Around 60% of economic UK rock iron ore formations contain over 0.2%P. Under fully reducing conditions, both in liquid-state (cast iron) and solid-state bloomery smelting (direct reduction) processes, such rock ores would be predicted to produce phosphoric iron, and bog iron ores even more so. Ore-metal-slag phosphorus ratios for bloomery iron are derived here, by means of: laboratory experiments; full-scale experimental bloomery smelting; and analysis of remains from three Medieval and two Late Roman-Iron Age iron production sites in England and the Netherlands. Archaeological ore, slag, metal residues (gromps), and iron artefacts were analysed by metallography, SEM-EDS, EPMA, and XRD. The effects of forging and carburising on phosphoric iron were studied by experiment and artefact analysis. The ore to slag %P ratio for solid-state reduction was determined to range from 1:1.2 to 1: 1.8. The ore to metal %P ratio varied from 1:0.2 to 1:0.7-1.4, depending on furnace operating conditions. Archaeological phosphoric iron and steel microstructures resulting from non-equilibrium reduction, heat treatment, and mechanical processing are presented to define the technology of early phosphoric iron. Microstructures were identified by a combination of metallography and chemical analysis. The phosphoric iron artefacts examined appear to be fully functional objects, some cold-worked and carburised. Modern concepts of 'quality' and workability are shown to be inapplicable to the archaeological material.

This project presents a study of iron technology in Early Medieval (fifth to eleventh centuries AD) Britain through the examination of iron found in settlement contexts. This is a period characterized by significant cultural, political and social changes. The effect of these changes on iron technology has never been investigated on a large scale. Previous studies on iron focused either on individual sites or on single artefact types, and did not provide any clear multi-region interpretive framework. A longstanding problem has been in identifying the extent of usage of a key alloy: phosphoric iron. This research project examined iron assemblages from eight settlement sites of varying size, culture, economic and social status from across Britain. From each settlement a mixed assemblage of iron artefacts was sampled, including edged tools, items of personal adornment, construction materials, and craft tools. Analysis was by traditional archaeometallurgical techniques alongside SEM-EDS elemental analysis. Alloy usage, specifically relating to phosphoric iron, was examined and the manufacturing techniques assessed. It was shown that elemental analysis is the only reliable method to determine the presence of phosphorus in iron and demonstrated that the traditional phosphoric indicators as observed during optical microscopy are insufficient. Results were subjected to a series of comparisons based on settlement size, the inferred social status, and cultural affinities. The results demonstrate the high technological level of iron artefact production across the country. All areas had access to the full range of iron alloys and employed a highly developed range of smithing techniques. Phosphoric iron was a prevalent alloy in this period. Based on these results, a model of the Early Medieval iron industry is generated, suggesting a vibrant economy in which both local and traded irons were significant. / The accompanying data files and image files are not available online.

After carbon, phosphorus is the most commonly detected element in archaeological iron. The typical phosphoric iron range is 0.1wt% to 1wt%P. The predominant source of phosphorus in iron is the ore smelted. Around 60% of economic UK rock iron ore formations contain over 0.2%P. Under fully reducing conditions, both in liquid-state (cast iron) and solid-state bloomery smelting (direct reduction) processes, such rock ores would be predicted to produce phosphoric iron, and bog iron ores even more so. Ore-metal-slag phosphorus ratios for bloomery iron are derived here, by means of: laboratory experiments; full-scale experimental bloomery smelting; and analysis of remains from three Medieval and two Late Roman-Iron Age iron production sites in England and the Netherlands. Archaeological ore, slag, metal residues (gromps), and iron artefacts were analysed by metallography, SEM-EDS, EPMA, and XRD. The effects of forging and carburising on phosphoric iron were studied by experiment and artefact analysis. The ore to slag %P ratio for solid-state reduction was determined to range from 1:1.2 to 1: 1.8. The ore to metal %P ratio varied from 1:0.2 to 1:0.7 ¿ 1.4, depending on furnace operating conditions. Archaeological phosphoric iron and steel microstructures resulting from non-equilibrium reduction, heat treatment, and mechanical processing are presented to define the technology of early phosphoric iron. Microstructures were identified by a combination of metallography and chemical analysis. The phosphoric iron artefacts examined appear to be fully functional objects, some cold-worked and carburised. Modern concepts of 'quality' and workability are shown to be inapplicable to the archaeological material.

The Gotlandic smith has been depicted on several picture stones and is a subject of fear and respect in the Old Norse sagas. Their technological prowess can be identified through their skilful work and through the stories told about them, but one must delve deeper to identify the smith-craft itself. This thesis seeks to apply the practice of bone-smithing on the osteological material from the Gotlandic site of “Signallottan” located about a kilometre southeast of the Hanseatic walled city of Visby, a site which was excavated in 2018 to get a broader understanding of the site’s previous uses. In addition to this, an osteological and spatial analysis will be carried out to identify the role of the smith and the use of bones in smithing, as well as a literature study of texts depicting or discussing the smith from the perspective of the Icelandic sagas. The thesis will focus on the application of theoretical frameworks with their basis in materiality, agency, and entanglement to interpret what activities can be identified in Signallottan through the current analyses in correlation with the extensive previous identification of osteological material from the site. This thesis will seek to identify the animal species that are present in the osteological material as well as the degree of cremation of the bones, which could imply that bones were used in smithing practice and ritual during the Viking Age. Around 2,5kg of bones were analysed during the thesis, a majority of which were burnt. The spatial analysis of the site, which was carried out through GIS, reveals a connection between finds of iron, slag, and bone together with oxide scale to form the interpretation of the site as having been used for smithing, that may have used bone as fuel during the carbonisation-process. The smithing practices during the Viking Age are deemed to be a supernaturally connected practice with transformative implications of seiðr, old Norse magic, but are also practices that were highly dependent on the craftsman’s skill and a network of trade to receive the materials necessary for larger-scale production in an agricultural society.