Highly significant archaeological find as tiny 2000-year-old glass beads recovered from Caithness soil samples – shows international trade existed and recycling
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Careful sifting of soil samples from an archaeological site in Caithness has revealed several minuscule pieces of Iron Age jewellery that could originate from recycled Roman glass.
The post-excavation work involved processing soil samples taken from Swartigill near Thrumster and has revealed three blue glass beads that have been carefully worked and measure around 2mm across.
Martin Carruthers of UHI Archaeology Institute in Orkney was a project leader at the dig and called the discovery of the micro-artefacts as very exciting and significant.
Mr Carruthers said: "We have made a rather exciting find – or, rather, three exciting finds – from the routine task of processing environmental samples from the excavations at Swartigill, Caithness."
He said that the investigation included wet-sieving of soil samples, a process designed to recover charred plant remains, grains and seeds, or scraps of burnt bone, in order to "build a picture of the ancient environment".
"This is an incredibly informative process in its own right, providing insight into the natural and farmed landscape that the occupants of sites like Swartigill inhabited. At the same time, an added bonus of this process is that we often recover 'micro-artefacts'. These are tiny objects, often fragments of artefacts that are too small to reasonably expect to recover during excavation itself."
During recent sample-processing, UHI students Cecily and Travis were sorting through the contents of several samples when they discerned some very "beautiful and colourful glass beads" amongst the organic fragments in the sample and measuring around 2mm across.
Mr Carruthers added: "They are a beautiful light blue in colour and annular ordisc shaped. Iron Age glass beads are a fairly well-known occurrence on Northern Scottish Iron Age archaeological sites, however, the beads from Swartigill belong to a class of tiny glass beads that have really only come to light in fairly recent excavations. They are known as minuscule beads."
Recent chemical analyses of glass beads from Scottish Iron Age sites shows the raw material for making the beads was almost always recycled Roman glass from vessels and other objects. Vivid colours of glass, like blue and yellow, can be chemically traced showing they originate from areas as far away as the Syria/Palestine region of the eastern Mediterranean region.
"It’s quite thought-provoking to contemplate the long treks and sea journeys that these raw materials undertook. How many ancient hands and various places did the glass pass through in order to reach Northern Scotland over 2000 years ago where it was finally recycled into beautiful beads to be worn on the body or to decorate textiles?"
Glass bead-making appears to have been limited to a broad area of north-east mainland Scotland, but beads were distributed from there to Atlantic Scotland, across the entirety of the Highlands and Islands. "These include, we now know, sites like Swartigill, via some mechanism of trade or exchange," said Mr Carruthers.
As objects worn on the body during the Iron Age, minuscule beads are so small that they would be difficult to observe as individual items. Relatively large numbers of the beads would be required to make them visible enough to take advantage of their brilliant vivid colour.
It is likely that minuscule beads were actually part of more complex arrays of multiple-beaded objects, such as multi-strand necklaces, or perhaps embroidered on to textile garments, hems and plaits as part of clothing and headgear. They may even have been threaded onto people’s hair.
Since the beads were all found close together, it seems likely they came from a single piece of jewellery or an embroidered object designed to draw attention to the wearer. The blue colour could convey a message and possibly signify the sea or the sky. In many bead traditions they are used to ward-off the “evil eye” and resist malicious forces that might be directed at the wearer.
The beads may have been deliberately placed in the souterrain structure that forms part of the site – an underground passage that may have been used as a larder to store food – and may have been put there when it was being built as an offering.
Mr Carruthers continued: "The location and placement of the beads may, then, be no mere accidental loss and might give us an insight into measures taken to initiate important new buildings in the Iron Age."
He describes the discovery at Swartigill as "significant and perhaps quite telling". Compared to other monumental structures from the Iron Age, such as brochs, the Swartigill site possesses relatively thin-walled buildings that must have been fairly low, and these sat in a portion of the land that is tucked down in a little valley of the Swartigill Burn, quite unobtrusive in its nature.
"It would be all too tempting, then, to view Swartigill as a modest, low-key settlement whose occupants wrested a living from the less-than-best farmland. Perhaps, Swartigill occupied a lesser position in a hierarchical social structure, an outlying settlement under the authority of the much more substantial broch at Thrumster Mains just over a kilometre to the south-east?"
Other significant finds include a small fragment of a bronze decorative object, and two shale/cannel coal bangle fragments suggesting that the inhabitants had "the wherewithal to procure them and the confidence to wear and display them".
"These were not necessarily the actions of a down-at-heel peasant settlement scratching a subsistence-based, hand-to-mouth existence. And this is where the discovery of tiny artefacts like the minuscule glass beads comes in, helping us gauge the character of the community who lived at the site two millennia ago."
Islay Macleod, director of Yarrows Heritage Trust (YHT) which organised the dig, called the Swartigill excavation "one of the most significant finds in the county since the Victorian era" and says there is evidence that the prehistoric settlement may be much bigger than originally thought.
"We know there is building work further up the burn to the west which is probably part of this same site and it appears to be a village."
The 2021 dig was paid for by the Lybster and Tannach Informal Learning Fund, along with the Camster and Tannach District Foundation Scotland funds. YHT is raising money for its 2022 dig and is looking for volunteers to help out. More information on can be found at: www.yarrowsheritagetrust.co.uk
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