Case Study: Nybster Broch

Susan Kruse

Caithness has the largest density of known brochs in the Highlands, although very few survive with substantial remains. Many were excavated in the late 1800s/early 1900s, providing a wealth of artefactual evidence, although confusing stratigraphy and interpretation. Recent work, particularly by AOC Archaeology and Caithness Archaeological Trust, has provided modern and well-dated excavations of some brochs, and has called into question the nature of some of these structures and their construction details.

Nybster broch (MHG1593) is situated on a coastal promontory with a rampart, and a large circular building surrounded by various cellular outbuildings (Figures 1-2). It was excavated by Tress Barry 1895–1896.  Since then it has seen survey, laser scanning and excavation in the 2000s, most recently by AOC and Caithness Archaeological Trust in a community excavation in 2011 (Figure 3).

Aerial view of broch and surrounding buildings located on a promontory.
Figure 1: Oblique aerial view of Nybster Broch and Nybster Commemorative Monument, looking SSE. ©HES
Bases of stone walls from a roundhouse.
Figure 2: General view of the roundhouse, taken from the east. ©AOC Archaeology
Seven people excavating a building, while a group of adults and children are gathered outside of the excavation area.
Figure 3: A community excavation at Nybster Broch in 2011. ©AOC Archaeology

The first construction at the site was the defensive rampart which was multi-phased. Its first phase was between the Middle Bronze Age and early centuries AD. At some point between the 1st and 4th centuries AD this enclosure was modified, to produce a structure similar to a blockhouse such as are found at Orkney and Shetland.

The roundhouse wall has an internal diameter of 6.24m, with wall thickness averaging 4.7m, the largest wall to diameter ratio known for Atlantic roundhouses. Yet the small interior shows that it would have been more modest than other Caithness brochs and roundhouses. No intramural features survive, despite the thick wall, though it is possible that they were raised about the floor level, as can be demonstrated at Crosskirk broch in Caithness and Howe in Orkney. On the other hand, some other sites in the area also termed ‘brochs’ such as Whitegate, also have no evidence of intramural features, suggesting that this form of construction was a local Caithness variant tradition in a landscape which also had more classic brochs, such as Keiss Road (MHG1650) and Keiss Harbour (MHG1659) brochs.

Cellular buildings which occur around some brochs are often interpreted as much later, into the early medieval Period. The excavations at Nybster showed, however, that at this site they were Late Iron Age, with the earliest phase of one dating between 2nd century BC and 1st century AD, and later phases and other outbuildings between the 1st and 3rd centuries AD (Figure 4).  At Nybster outbuildings included a living area with hearth, oven, stone-lined tank and subsidiary cells. The dating suggests that these buildings formed a village, clustering around an imposing roundhouse. The dating of the roundhouse is based on artefacts, and assumed to be contemporary with the outbuildings. In 2017 two antler long-handled combs were dated, providing dates of AD 49–120 and AD 27–126.

Grass topped stone wall bases from a building.
Figure 4: Outbuilding 5 and defensive outwork, taken from the west, by Graeme Cavers. © AOC Archaeology

The Tress Barry and 2011 excavations uncovered a range of artefacts including stone, bone and ceramics and spelt grains. Most relate to everyday life, especially food processing and consumption, with evidence of farming, fishing, animal husbandry and wild food gathering, but there are also objects for personal adornment. Gaming pieces hint of leisure activity. Tools suggest leatherworking, bone working, textile production and ceramic industries. Whetstones and anvils suggest use and sharpening of iron objects. The discovery of a Roman melon bead and Samian ware, together with evidence of non-ferrous metalworking, indicate that Nybster village must be seen as a high-status settlement, able to import and manufacture exotics.

Of particular interest was the discovery of several stone settings cut into the rubble of the rampart, creating a cist-like structure (Figure 5). The fill of one cist included pottery sherds and a worked tooth or tusk, while another included teeth, a fragment of a crucible and a strip of copper alloy. In Caithness there are human burials at some of the broch sites, traditionally interpreted as later early medieval burials at abandoned later prehistoric monuments. Dating is the issue, and more work needs to be done. At Nybster no human bone was identified in the recent excavations, but the structures strongly resemble early medieval cists. Tress Barry’s excavations are said to have uncovered fragments of human skulls, but it is not known where these were found nor what happened to them.

Shaft lined with stones with measurement devices in it.
Figure 5: Stone setting [5068] post-excavation. ©AOC Archaeology

The most recent building activity on the site was a memorial to Tress Barry built in the 20th century next to the roundhouse entrance, and then moved away from the site in the 1980s.

The site is important for showing the complexity encompassed by the term Highland broch, and for providing dating of the outbuildings around some of these structures, together with valuable artefactual material.

Further information

Heald, Andy and Cavers, Graeme 2012. Community Excavations at Nybster Broch 2011: Final Report. (AOC DSR. Attached to MHG1593). 

Heald, Andrew and Barber, John 2015. Caithness Archaeology: Aspects of Prehistory, Whittles Publishing: Dunbeath