A broch is an Iron Age dry-stone circular tower found widely across the Western Isles and adjacent areas of the Scottish mainland. Brochs were built during a relatively short period of time, from the late 1st millennium BCE and early 1st millennium AD.^[1] All but a handful have been discovered in the northern part of the mainland and the Western and Northern Isles.^[2]

Brochs can be up to 30 metres (98 ft) in diameter and 15 metres (49 ft) wide, with hollow, double-skinned walls up to 3 metres (10 ft) thick. The central court contained chambers, and in some cases was roofed over.^[1] Brochs usually have a single entrance with bar-holes, door-checks and lintels, and a spiral staircase winding upwards between the inner and outer walls. Most brochs have scarcements (ledges) which may have supported either a wooden floor or a roof.^[2]

The word broch is derived from the Norse word borg, meaning “fort”, probably first applied to these by then abandoned structures by 9th-century Viking raiders. From the late 19th-century, archaeologists adopted the term to characterise a subtype of dry-stone roundhouse,^[3] but the modern view is that brochs were fortified dwellings rather than forts.^[4]

According to Historic Environment ScotlandExecutive non-departmental public body responsible for investigating, caring for and promoting Scotland's historic environment., the country has more than 500 brochs.^[5] The archaeologist Ian Armit has argued that they are far too common to have been the homes of chiefs or kings, and are more likely to have been inhabited by extended family groups who farmed the surrounding lands.^[6]

External links

• Brochs: The mysterious circular symbols of Scotland, part of BBC Reel’s Ancient Mysteries playlist