Analyses experimental smelting and smithing assemblages (including ore, furnace lining, fuel and slag) in order to compare these to slag inclusions in the resulting bloom and worked objects, and then to explore the relationships between ore, slag and slag inclusions. This is taken to indicate that the composition of slag inclusions most closely relates to the smelting slag produced, whereas provenance to a specific ore would be difficult due to the chemical variability derived from furnace lining, fuel and any fluxes used. Some compounds in the slag inclusions are particularly affected during smithing of the artefact, i.e. those present in the sand flux and fuel used. However, trends are observed in the K2O/MgO, MnO/SiO2, Al2O3/SiO2, Al2O3/MgO, Al2O3/K2O and Al2O3/CaO ratios that allow comparison between slag inclusions and smelting slag in these experiments, and may therefore be used during other provenancing attempts.