Iron Age

The Iron Age is arguably Shetland’s most visible and the most extensively researched archaeological period. There are more radiocarbon dates for Shetland’s Iron Age than there are for all other periods combined and sites with Iron Age material have been the subject of several longstanding research projects. The signature Iron Age sites (namely brochs but also wheelhouses in the later Iron Age), are by their very nature monumental and have therefore tended to dominate perception of later prehistoric landscapes.

In Shetland, there is an astonishingly large number of well-preserved brochs, with more 120 of these sites recorded in the HER. Some, but by no means all, are accompanied by nucleated settlements, suggesting complex social dynamics at play alongside the development of these settlements. But seemingly isolated examples are also common. A preoccupation with brochs, and other forms of monumental domestic architecture arguably persists in narratives for the Atlantic Scottish Iron Age more widely and Shetland is no different in this respect.

Antiquarians and early 20th century researchers, attracted by the monumentality of these sites, investigated numerous brochs across Shetland and in doing so established a strong baseline for future researchers. Late 20th century investigations at Jarlshof, followed by Curle and then Hamilton’s excavations in the 1930s and 1950s respectively, uncovered a well-preserved Iron Age settlement that included a broch as well as a series of wheelhouse structures. Later in the 1950s Hamilton’s continued interest in Shetland’s Iron Age saw the extensive excavation of Clickhimin broch, revealing complex occupation sequences (Hamilton 1968).

Between 1989 and 1990, Cardiff University’s excavation of Upper Scalloway broch provided significant insights into Shetland’s broch economy and social structure, complementing wider Atlantic Iron Age studies of the time (Sharples 2002, 2003). From the mid-1990s to the mid-2000s, the excavation of a broch and wider Iron Age village at Old Scatness was run by Shetland Amenity Trust in collaboration with researchers from Bradford University (Dockrill et al 2015). Fojut’s (1989) analysis of Shetland’s monumental Iron Age landscape has also been influential, particularly from a methodological perspective.

Monumental architecture as a feature of multiperiod settlements is another key characteristic of Shetland’s Iron Age archaeological record and its associated research. Excavations at Jarlshof for example showcased a long sequence of occupation from the Neolithic through the Iron Age to the Viking period. Similarly, Old Scatness is notable for provided insight into settlement continuity from the Iron Age into the Pictish and Norse periods (Dockrill et al 2010, 2019) and at Upper Scalloway, finds included a Bronze Age cremation urn, evidence of later Iron Age occupation, and medieval burials (Sharples 2002, Williamson 2020). These three sites are the key reference points for Iron Age research across Shetland, between them the subject of more than 35 years of excavation work. It is also noteworthy that more than 50% of Shetland’s Iron Age radiocarbon dates come from Old Scatness, with a further 10% from Upper Scalloway, further highlighting the contribution of these sites to our understanding of Shetland’s Iron Age chronology. Research at Old Scatness has been particularly significant in terms of developing and refining OSL dating techniques (Outram et al 2010) and relatedly contributing to debates concerning the origins of broch arhcitecture and the chronology of their subsequent development (Dockrill et al 2007).

Although broch and wheelhouse sites have historically attracted substantial researcher attention, there still remain some pressing knowledge gaps for Shetland’s Iron Age. The relationship between nucleated settlements and brochs needs further study—were they contemporary or did they develop in phases? Whilst brochs dominate Shetland’s Iron Age landscape, their construction and function clearly vary across the archipelago and across the wider Scottish island landscape. How do Shetland’s brochs compare to those in the Hebrides and Orkney? Were broch villages common or exceptional across Shetland, and how do they relate to and compare with Orcadian examples? Further research is needed to clarify the development, purpose, and relation to surrounding settlements.

Beyond brochs and wheelhouses, other Iron Age site types require attention including crannogs, blockhouses and souterrains. Crannogs in Shetland are under-researched, with little understanding of their construction timeline and use compared to mainland Scotland. Recent research into Shetland’s crannogs has identified 34 sites, including some linked to broch sites, raising further questions about their construction and function (Stratigos 2021). Blockhouses, rare outwith Shetland, also require further study regarding their purpose, origins, and relationship to the wider broch phenomenon. Souterrains in Shetland, as elsewhere, are in need of further excavation and dating work if we are to understand their role and significance across Iron Age society.

Economically, Shetland’s Iron Age was based on mixed farming, with evidence of controlled barley production, livestock management, and use of potential trade networks. However, surviving metalwork is scarce, raising questions about local production versus imports. Wood resources were also limited, suggesting reliance on driftwood and careful management. Further studies on pollen and environmental data are required to help clarify land use practices. Shetland’s role in wider Iron Age Atlantic networks, including its relationship with Pictish culture and wider economic connections, is still unclear. Were local production centres supplying only Shetland, or did they engage in external trade?

The extent to which later Iron age communities across Shetland identified with Pictish culture is also uncertain. There is also limited understanding of pre-Christian belief systems due to a scarcity of burial evidence. While past research has been fragmented, ongoing interdisciplinary studies using modern techniques offer exciting opportunities to refine Shetland’s Iron Age chronology and social history. Future studies will benefit from a focus on systematic dating of settlements, remote sensing for undiscovered sites, and interdisciplinary approaches combining archaeology, environmental science, and material analysis. Expanding excavation and post-excavation analysis, particularly in a developer-funded context, will be essential for addressing existing knowledge gaps.

You can download the datasheet for more information on the Iron Age sites and c14 dates from Shetland.

Iron Age Research Questions