6.5.2 Metalworking

Evidence of metalworking is not common in Scotland, though there is evidence in the Highland Region for manufacture that used moulds and crucibles from a variety of contexts (Table 6.11).

The use of metal objects and the knowledge of how to prospect for, process and work metal were introduced to Britain by immigrants from the Continent – the ‘Beaker People’ (Parker Pearson et al 2019). Copper from the Beaker-associated mine at Ross Island, County Kerry, southwest Ireland, was used to make the Chalcolithic copper axeheads and at least some of the copper halberds found in the Highland Region. This material continued to be used when bronze production started during the 22nd century BC. Whether the earliest copper artefacts in the Highland Region were imported as finished artefacts or as raw copper is unclear. Needham (2004, fig 19.15), however, has underlined the fact that there is a northeast Scottish style of halberd, the Auchingoul type, which implies that copper was being reworked into forms that suited local tastes.

The connection with Ireland remained strong and indeed was crucially important once bronze started to be used in Scotland. The southeastern Highlands, along with parts of Moray and Aberdeenshire, became a centre for the production of bronze flat axeheads and other bronze and copper artefacts at this time. The name ‘Migdale-Marnoch industry’ has been given to this phenomenon (Coles 1969 drawing on earlier work by Stuart Piggott), and the nature, extent and significance of this phenomenon has been discussed by Needham (2004; Cowie 1988; ScARF Bronze Age section 2.2). Single-valve stone moulds have been found in the Highland Region at Strath Conon (MHG7909) and Ferintosh (MHG9024), and further examples are known from Moray, Nairn and Aberdeenshire, including at Culbin Sands (Table 6.11; see Needham 2004, fig 19.8 for a distribution map).

The copper used in this ‘industry’ almost certainly travelled to northeast Scotland via the north of Ireland and the Great Glen. The tin that was alloyed with the copper to form bronze almost certainly originated in southwest England, most probably Cornwall. Whether the metal that entered the ‘Migdale-Marnoch’ system came in the form of already-made bronze or as ingots of copper and ingots of tin is not known with certainty. It is worth noting, however, that the existence of copper ingots is known from elsewhere in Scotland, for example in Burreldales and Fyvie, Aberdeenshire (Coles 1969, 91). The circulation of metallic tin in Scotland is attested by the tin inlaid into a jet V-perforated button found at Rameldry Farm, Fife (Baker et al 2003; Sheridan 2017b; Chapter 6.4.3.3).

Control over the flow of metal clearly offered an opportunity for some individuals to acquire both power and wealth and to enhance their status. This is reflected in the rich Early Bronze Age funerary monuments and material culture found in Kilmartin Glen, near the southern end of the Great Glen (Sheridan 2012e), and also, arguably, by the richly equipped Early Bronze Age graves in the Highland Region. The Chalcolithic or Earliest Bronze Age male grave at Culduthel (MHG3776) underlines the connection with Ireland: this individual was buried with a fine Beaker; elite archery gear, including a wristguard of Great Langdale tuff embellished with gold-capped copper rivets, fire-making equipment and an amber bead. The isotopic analysis revealed that this individual grew up in County Antrim, Ireland (Parker Pearson et al 2019, 395, 448), and it is not beyond the bounds of possibility that he was involved in controlling the northeasterly flow of metal from Ireland. Similarly, the individuals buried at Seafield West may also have been involved in this movement of metal: the Bowl Food Vessel found in one grave is of Irish style (Case Study Seafield West Bronze Age Cemetery).

That bronze artefacts continued to be produced after the Early Bronze Age in the Highland Region is clear from the evidence at Langdale (MHG12473), Kyle of Oykel (MHG11884; MHG10068) and Inshoch Wood (MHG7060). The Middle Bronze Age steatite mould for a spearhead found at Langdale in Strathnaver and the metalworking tools found at Kyle of Oykel and Inshoch Wood are two examples (Table 6.11); portable anvils were found in both places. At Inshoch Wood there was also a socketed hammer and a fragment of a spearhead, possibly destined for recycling. Portable moulds and anvils were found along the river Oykel and at Inshoch Wood. The portability of moulds could be taken to indicate that specialist metalworkers might have been peripatetic, travelling around to supply the needs of communities, rather than being based in workshops. Such small-scale metalworking activity would leave very few or no traces.

Late Bronze Age metalworking in the Highland Region is attested in several locations. The evidence consists of clay moulds for the manufacture of swords at Seafield West (MHG3944; Cressey and Anderson 2011; Case Study Seafield West Bronze Age Cemetery); axeheads at Stittenham, Rosskeen (MHG8165; Clark et al 2017); sickles and other tools at Bellfield, North Kessock (MHG58023; Clark et al 2017; Hatherley and Scholma-Mason forthcoming); crucibles at Galmisdale on Eigg (MHG38076; Cowie 2002); and mis-cast objects and casting jets at Baile-a-Chladaidh, Dores (MHG59131; Clark et al 2017).

Of note is the possible association of metalworking equipment with the grave of an adult inhumation in a cist at Golspie (MHG10894; Woodham and MacKenzie 1957). Fragments of clay moulds for uncertain objects and a heavily worn perforated stone pendant, possibly a whetstone, were found with cremated remains which produced a radiocarbon date of the Late Bronze Age (Parker Pearson et al 2019, Appendix 2). However, the moulds do not appear to stylistically match any Late Bronze Age artefacts, and they may represent a later insertion possibly in the medieval period. If this is a genuine association, however, this site is significant as it is the only Late Bronze Age grave in Britain where metalworking material is associated with human remains. Further work is required to clarify the situation.

Evidence that Bronze Age bronzeworking techniques continued after the first appearance of iron objects in Scotland is found at Bellfield, Stittenham, and Poolewe. At Bellfield, North Kessock, the moulds came from pits in an Early Iron Age context, but most of the objects being manufactured were very much in the late Bronze Age tradition. The evidence from Bellfield, North Kessock, suggests such sites were perhaps more common, but survival depends on modern excavation techniques, preservation and an awareness of fragmentary clay moulds in the archaeological record. The Stittenham moulds were for producing Sompting-type axeheads, which are now dated to the very Earliest Iron Age (O’Connor 2007; Needham 2007). Fragments of the haft in a Sompting-type axehead from the hoard found in Poolewe, Wester Ross, also confirmed this very Early Iron Age date (MHG7755; Knight et al 2021). This shows the continued importance for non-ferrous metalworking in the Highlands even as ironworking became more common.

With regards the provenance of the metals used during the Chalcolithic and Bronze Age, as National ScARF Bronze Age section 2.2 noted, there is no proof that Scottish copper was used. Metal analyses have clearly demonstrated that copper was imported from the Ross Island mine in southwest Ireland during the Chalcolithic and Early Bronze Age. The copper supply diversified from around 2000 BC as new mines were opened elsewhere in Ireland and Britain and recycling intensified. Compositional analyses of the Poolewe hoard indicated that new metal, either as ingots or as trade objects, continued to enter the supply system until at least 800 BC, during a period when bronzeworking has traditionally been seen as declining (Knight et al 2021).

Tin, in at least the early stages, would have been imported from southwest England, probably in ingot form, though whether it travelled directly, via Ireland or both is not clear.  Many Middle and Late Bronze Age objects were probably made by melting down earlier out of fashion objects, so it is unknown how long the importation of pure metallic tin continued. Clearly, sufficient tin was circulating during the Early Bronze Age to allow the makers of some Migdale-type axeheads to embellish these objects and coat their surfaces with tin (Close-Brooks and Coles 1980; Needham and Kinnes 1981; Meeks 1986). Tinning was a technically demanding process, and while useful metallurgical research has already been undertaken on how it was achieved (Needham and Kinnes 1981; Meeks 1986), further research and experimental replication needs to be undertaken to understand the process better.

The sourcing of gold used to make artefacts, the issues involved in provenancing artefactual gold, and the question of whether any Scottish gold sources were exploited during the Chalcolithic and Early Bronze Age are all matters that are actively being pursued as a result of an international AHRC-funded project led by Alison Sheridan and Jana Horak. This is the same team that began work after the National ScARF project. Traditionally it has been assumed that Irish gold was used to make many Bronze Age objects, and while this may be true of some Middle and Late Bronze Age objects, important work by Standish (et al 2015) has indicated otherwise. Lead isotope analysis of Early Bronze Age artefacts in Ireland and Scotland has shown that Cornwall was an important source of gold during the Early Bronze Age. While most of the Scottish work remains to be published, Standish’s (in Brophy and Noble 2021) analysis of a gold pommel band for a dagger from Forteviot, Perth and Kinross, has shown that its composition is comparable with that of Irish Early Bronze Age artefacts, so an ultimate origin of the gold in Cornwall seems likely (also see Chris Standish’s podcast on his gold work).

There is currently no evidence for the exploitation of the deposits of gold around Kildonan, Sutherland during prehistory, despite the 19th century AD goldrush there (Chapter 10.5; ScARF Bronze Age section 4.5.1). The Heights of Brae hoard was analysed using X-ray fluorescence spectrometry shortly after its discovery (MHG8921; Clarke and Kemp 1984; Case Study Heights of Brae Hoard); the compositional data needs to be reassessed in the light of what is now known about the compositional patterning of Late Bronze Age gold; this would make a useful case study. This hoard is particularly interesting since the style of the artefacts is Irish, suggesting importation from Ireland, and several of the objects appear not to have been finished. Additionally the Culduthel rivet-caps need to be analysed non-destructively to determine whether their composition matches that of Early Bronze Age or Chalcolithic artefacts in Scotland and Ireland, for which a source other than Cornwall seems likely.

Outstanding questions relating to metalworking for this period in the Highland Region include that of the source of the steatite used to make the Middle Bronze Age and earliest Iron Age moulds found in Langdale and Stittenham. Was this the same source as was used for the ‘talc’ (steatite) filler used in Middle to Late Bronze Age pottery in the Highland Region, as at Lairg? Further research questions for metalworking are outlined in Chapter 6.9.