A number of settlements from the Iron Age were enclosed, either by walls, wooden palisades or within ramparts on elevated locations. Enclosure does not necessarily equate with high social status. It is noteworthy that one of the wealthiest Iron Age settlements in the Highlands, at Culduthel, was not enclosed, nor was the comparable settlement at Birnie in Moray (ScARF Iron Age section 6.3). In addition to the hillforts, duns, palisaded enclosures and crannogs discussed below, there are also examples of smaller enclosures that were not houses. Any structure greater than 20m in diameter was probably not able to be roofed using Iron Age technologies and this diameter is therefore seen as the threshold to distinguish houses from enclosures (Harding 1984, 219).
Few enclosures have been explored and dated in the Highlands. An exception is a ditched enclosure at Lairg which enclosed around 26m, that dates to around 400–200 BC. It was not on a hilltop, nor was it possible to determine if it had contained buildings, although there was a fair amount of charcoal present at the site likely due to human activity (McCullagh and Tipping 1998, 69–72).
Hillforts and Duns
For the distribution of hillforts and duns in the region see Map 7.1 below; and for further details see Datasheet 7.1.
|Easter Rarichie||ER||7 dates 400 – 200 BC||Partial excavation of stone built simple roundhouse with internal postholes, with occupation between house and rampart. Built over earlier occupation.||MHG44719; Atlas of Hillforts SC2912; Hatherley 2014|
|Craig Phadrig||I||Various||Multi-period vitrified hillfort, with new and old radiocarbon dates. Initial destruction 4th to 3rd century BC. Dates from the 1970s are too broad to be useful||MHG3809; Small & Cottram 1972; Peteranna & Birch 2018|
|Dun Deardail||L||Various: 5th – 2nd century BC||Vitrified hillfort. No later reoccupation||MHG4348; Ritchie 2018|
Case Study: Dun Deardail Iron Age Hillfort
All dates cal at 95.4% probability. For full details of dates, see Datasheet 2.1
The terms ‘hillfort’ and ‘dun’ refer to enclosed or defended sites on elevated positions, which could have contained none or multiple buildings. When discussing regional trends in hillforts and enclosures, National ScARF highlighted the lack of information from the Highlands, noting that ‘any work in this area would be beneficial’ (ScARF Iron Age section 6.8). Since then there have been few excavations in the Highlands on these sites and even fewer with dating (see Table 7.2).
Archaeologists are still a long way from understanding the function of hillforts. As the National ScARF stated: ‘It is now generally accepted that there is no definitive interpretation of the function of hillforts and enclosures, which probably conveyed a variety of ideological statements at different times and places to different people’. Excavation results elsewhere in Scotland suggest some were occupied both long term and seasonally (ScARF Iron Age section 6.7). At present there is little evidence in the Highlands to add to this debate; more dated examples are needed.
The recent online Atlas of Hillforts of Britain and Ireland provides an assessment of all known hillforts. This project defined hillforts as having a prominent topographic position and enclosing outworks of an area greater than 0.2 hectares. Conversely, 62% of the Highland sites generally accepted as hillforts are less than 0.2 hectares in area, showing a regional trend for smaller hillforts. In the Highlands the Atlas identified 154 confirmed and 42 possible hillforts, with an additional 12 sites being considered either unlikely or in needing of further survey (see Datasheet 7.1). The Atlas provides a very useful basis for addressing a variety of questions, such as entrance arrangements, size, evidence of vitrification and geographical distribution (see also ScARF Iron Age section 6.6).
Small hillforts have sometimes been called duns. Unhelpfully, the term ‘dun’ is also applied to some buildings which appear at elevated locations; this will be discussed in chapter 7.3.5. The defining characteristics of duns in the past appear to have been size of the structure combined with wall thickness (Harding 1984). Creating distinctions between hillforts and duns in this manner was already seen as unhelpful at the time of the National ScARF (Iron Age section 6.8), and the general trend towards smaller hillforts in the Highlands makes it even more so. The Highland HER records 221 duns. Of that 26 are unlikely identifications or need more information, 64 are rejects (natural, other buildings; galleried duns or roundhouses, or are not located) and 40 are considered hillforts by the Atlas of Hillforts. This leaves 91 possible duns (see Datasheet 7.1). The majority enclose areas of less than 20m in diameter. This begs the question, just what was inside or even if the walls were used structurally for a building. Analysis from an architectural perspective, and which focussed on wall thickness, can provide some insights for these remaining Dun sites (Romankiewicz 2009). However, in many Highland cases the term appears to be applied where preservation does not allow for a more detailed attribution. In most cases, the Highland sites recorded as duns are ruinous or have not had any fieldwork, so that their exact nature and purpose remain unclear.
The defining characteristic of the hillfort or dun is the enclosure wall. Where contemporary buildings are contained within them, the buildings are usually substantial stone-built structures, as discussed below. Occasionally, modern excavations with radiocarbon dating have shown the main building to be a simple roundhouse; for example, at Wester Rarichie (MHG8465) the roundhouse was constructed of turf (Hatherley 2014).
Hillforts and duns were clearly positioned in the landscape to have commanding views and presence. Some are in areas of good agricultural land, for example Easter and Wester Rarichie (MHG8465; MHG44719), but others, particularly coastal promontory forts are more remote (ScARF Iron Age section 6.2). Many clearly consumed extensive resources and required a large workforce for their construction, but the social organisation behind this process remains unclear (ScARF Iron Age section 6.6; Barber 2017). The logistics and practical knowledge needed to build some of the Highland hillforts, such as the highest and one of the most remote in Scotland, Ben Griam Beg in Sutherland (MHG9658), provide a case in point (ScARF Iron Age section 6.8).
At Rahoy, Lochaber (traditionally classified as a dun), stone walls enclosed an area of around 12m in diameter (MHG487). The site when excavated by Childe and Thorneycroft (1938) in the 1930s, had excellent preservation, with good artefact and wood survival including of the floor levels and hearths. The excavators noted the possibility that there were upright timbers on postpads. These would leave little trace but would have supported a roof, fully covering the enclosed area. Others have interpreted the site as a robbed dun-house like Comar Wood (Peteranna and Birch 2017a, 37). MacKie (2007) suggested it might have been a wooden roundhouse that was protected by the massive walls.
There appear to be some clusters of hillforts and duns, for example in Strathglass, Inverness-shire or on Skye. This suggests that there might be regional preferences in some areas within the Highlands for small hillforts. Again, further dating, survey and excavation would provide evidence. The seeming preference for small hillforts and/or duns in southern Skye and Complex Atlantic Roundhouses (cARs) in northern Skye could be explored further, especially by looking at the sources of building materials.
Although more dating evidence is becoming available elsewhere, there are still questions about chronology and phasing at these sites. There have been suggestions that some hillforts date to the Late Bronze Age, but little evidence is available for Scotland as a whole (ScARF Iron Age section 6.5) and the Highlands in particular. Some earlier thermoluminescence dates are known, for example for Knockfarrel (MHG7152), but there is some question as to their reliability (Peteranna and Birch 2018, 79), and further work is needed. As Gordon Noble’s excavations on promontory forts are showing, many of these were used in the early medieval period (see Chapter 8.3), so without excavation they cannot be assumed to be Iron Age. Evidence elsewhere suggests that enclosures may have only been one of the phases at a site (ScARF Iron Age section 6.6), which cautions against dating the vast range of Highland hillforts and duns as used in a single event. Cnoc an Duin hillfort (MHG8188), Easter Ross, is generally considered to be an unfinished structure, and this provided an opportunity for dating and single-phase investigation.
Many of the Highland hillforts and some duns are vitrified (15% of the confirmed Highland hillforts). The predominant theory is that this was a deliberate action, even if it is still unclear exactly how the high temperatures were generated and sustained; however, accidental fires, fuelled by fierce Highland winds cannot be ruled out. If deliberate, vitrification does not appear to be a construction device (ScARF Iron Age section 6.6 with refs).