Brochs are among Scotland’s most iconic archaeological monuments. These drystone towers are some of the most remarkable buildings constructed in prehistoric Britain, and are some of the best preserved buildings of Iron Age date found anywhere in northern Europe. Found mainly in the north and western coastal regions of Scotland, they are characteristic of the Iron Age in the Atlantic parts of Scotland.
Dun Telve, Glenelg
Brochs were built in a range of sizes and to varying designs. However, they all share a range of structural features that make them very distinctive of Scottish prehistoric architecture. The key characteristic is the massive wall of the building, usually around 15 to 20m in external diameter. The walls of brochs can be up to 4m in thickness at ground level- sometimes almost as wide as the area they enclose. But what is unique about broch walls is the way they were built: the wall of the tower is in fact two walls, converging with height and tied together by a lintel stones that spanned the gap between. These gaps formed galleries which contained cells and staircases to the higher levels of the tower. Archaeologists and architects debate how this could have been done, but it seems most likely that the tower was completely roofed, creating a tall, multi-floored roundhouse.
Dun Dornadilla, Sutherland
Although all brochs were different, many were designed to be towers up to around 13m in height. The best preserved example of a broch tower is Mousa in Shetland, which survives to the height of its wall head. There are a handful of other sites that survive to similar heights (Dun Carloway, Dun Telve, Dun Troddan and Dun Dornadilla are good examples) but the majority of brochs are now reduced to only a metre or two in height. Nybster is an example of the latter: the broch- if it was ever a tower like Mousa- was probably dismantled in the later Iron Age, when the surrounding ‘Pictish’ period village began to grow.
When were they built?
The date that brochs began to be built in Scotland has been the source of a lot of debate in archaeology. Most were probably in use in the last two centuries BC and very early AD, but a number of sites have produced earlier dating evidence, suggesting that some brochs were being constructed by the 5th or even 6th centuries BC. The broch of Old Scatness in Shetland is key to this debate, and was built in the early Iron Age- around the middle of the first millennium BC.
Why did Iron Age people build stone towers?
Brochs represent a pinnacle in Iron Age architecture, and are undoubtedly masterworks in drystone engineering. To the societies that built and used them, however, they were more than just defensive strongholds, representing symbols of authority in the landscape used by communities to symbolically stake claims to their territories. Other forms of Iron Age settlement are similarly ostentatious, albeit in different ways, and like crannogs (artificial island settlements) and forts, brochs often sought to appear more defensive than they were in reality.
How long did people live in brochs in Scotland?
Almost all brochs that have been investigated in Scotland have produced evidence for activity over long periods of time- almost 1000 years in some cases. Broch settlements probably went through major changes throughout their lifespans, however, and by the late Iron Age and into the early historic period, most were probably out of use as towers. In many places, particularly in Caithness, Orkney and Shetland, village complexes grew around brochs; these were occupied throughout the Pictish and Norse periods, and some continued in use into the medieval centuries.
