In the northern periphery of the ‘lowland group’ for brochs (MacInnes 1985; Romankiewicz 2011), the uplands west of the River Tay contain a notable concentration of massive, stone-walled monumental roundhouses of around 12–18m internal diameter, with a variety of options for internal construction. They include some architectural features found on brochs, such as raised floors, and intramural cells and stairs. Six have been excavated: Borenich (MPK1248; Watson 1915), Litigan (MPK413; Taylor 1990) and Queen’s View (MPK1212; Taylor 1990), two at Aldclune (MPK3; Hingley et al 1998), and the Black Spout, Pitlochry (MPK1607; Strachan 2013). While Stewart (1969) and Taylor (1990) suggested the sites as an early medieval phenomenon, excavations at Aldclune confirm construction of one between the 1st and 2nd centuries BC and the other between the 2nd and 3rd centuries AD, with two phases of occupation at each site (Hingley et al 1998). The Black Spout was occupied between the late 3rd and late 2nd centuries BC. A number of these sites appear to have been reused, if not reoccupied, in the early medieval period (Strachan 2013, 36–37). The first lowland example has recently been identified within Moredun Top fort, Perth (MPK5232; Strachan et al forthcoming).
The discovery of a demolished broch within Castle Craig fort (MPK1399; Poller forthcoming) is significant. It is the only confirmed example where its scale and construction suggest a full broch tower, with the narrow entrance and battered external wall face associated with the class across Scotland. The structural viability of the building was afforded by the quality of the local stone as a building material, naturally breaking into even, flat slabs, though elsewhere the quality of stone may not always have been a consideration. Excavation suggests that the broch was burnt and levelled. The debris contains a rich assemblage of 1st–2nd centuries AD artefacts, including fragments of glass vessels and bronze objects including a patera (James 2011; 2012) which offer insight into connections between the broch community and the Roman Empire (Poller forthcoming). Radiocarbon dating of the fort indicates several phases of activity over the periods 400 BC to AD 50, AD 50–400 and post AD 800 (Poller pers comm) with the later dates confirming the continued importance of the site and relate to the fort constructed over the levelled broch (James 2011; Poller forthcoming). A similar accumulation of high-value material culture at this time can be seen in other lowland brochs such as Leckie (MacKie 2016) and Fairyknowe (Main 1999).
A broch suggested at Little Dunsinane, Collace, (MPK6571; RCAHMS 1994, 51, 74) could equally take the form of the monumental roundhouses of the uplands, rather than a broch proper, and only excavation can determine the answer. Recently, a monumental roundhouse was recently discovered within Moredun Top [MPK5232] fort on Moncreiffe Hill, Perth (Strachan et al forthcoming; Strachan et al 2020, 28). Initial dating suggests use around 400–100 BC, making it slightly earlier than the Black Spout and Aldclune sites (Strachan et al 2020, 32–33; Strachan et al forthcoming). While the interior produced a rich assemblage of artefacts and ecofacts, which provides extensive evidence for occupation and indicates a major burning and demolition event.
The nature of monuments also varies significantly across the region. Perhaps the most significant is the difference in settlement evidence east and west of the River Tay. To the west is a concentration of 60 monumental roundhouses, previously called ‘circular forts’ (Watson 1913), ‘ring-forts’ (Stewart 1969) and ‘homesteads’ (Taylor 1990), as well as duns and forts. These are noticeably absent to the east of the Tay, a fact which cannot be explained by survey bias, and which merits further consideration.