In archaeology, a broch /b r ɒ x / is an Iron Age building made of dry stone with hollow walls found in Scotland. Brochs are part of a group called "complex Atlantic roundhouse," a term created by Scottish archaeologists in the 1980s.
Brochs are round buildings found across northern and western Scotland. The word "broch" comes from the Lowland Scots word "brough," which means "fort." In the mid-1800s, Scottish historians called brochs "burgs," a word similar to the Old Norse "borg," which also means "fort." Brochs are sometimes called "dùns" in the west. They are the most impressive buildings in a group of complex structures found in northern Scotland. There are about 571 possible broch sites in Scotland, according to the Royal Commission on the Ancient and Historical Monuments of Scotland.
The origin of brochs is still being studied. In the mid-20th century, some archaeologists thought brochs were built by people from southern England who moved north. However, today, it is clear that brochs first appeared in what is now Scotland. The earliest brochs may have been built around 300 BC. Evidence suggests they were used mainly for defense or attack.
Brochs are mostly found in northern Scotland, with the highest numbers in Caithness, Sutherland, and the Northern Isles. A few are found in the Scottish Borders, near Dumfries and Galloway, and near Stirling. Early ideas suggested brochs were defensive structures where people and animals could take shelter. Some believed they were built by the Danes or Picts. From the 1930s to the 1960s, archaeologists thought brochs were like early castles where local leaders controlled nearby people.
However, the idea that brochs were castles was not supported by evidence in the 1980s. These archaeologists argued that brochs were not built for defense and may have been important homes that showed the power of wealthy families. However, there is no clear proof for this idea, and the large number of brochs makes it hard to explain their purpose. The article ends by saying brochs may have served multiple purposes, including defense, attack, and as symbols of status.
Origin and definition
The word "broch" comes from the Lowland Scots word "brough," which means "fort" among other things. In the mid-1800s, Scottish historians called brochs "burgs," after the Old Norse word "borg," which also means "fort." Place names in parts of Scotland with Scandinavian history, such as Burgawater and Burgan, show that "borg" was the older term used for these structures in the north. In western Scotland, brochs are often called "dùn." Historians began using the spelling "broch" in the 1870s.
A clear definition for the word "broch" has been difficult to create. Brochs are the most impressive type of roundhouse buildings found in Atlantic Scotland. The Shetland Amenity Trust lists about 120 sites in Shetland as possible broch locations, while the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS) identifies 571 possible broch sites across the country. Researcher Euan MacKie, using a strict definition, suggested there may be as few as 104 brochs in Scotland.
The origin of brochs is still being studied. In the 1940s, most archaeologists believed brochs, often called the "castles" of Iron Age leaders, were built by people who moved north after being displaced by Belgic tribes in southeast England around 100 BCE and later by the Roman invasion of southern Britain starting in 43 CE. However, it is now clear that the hollow-walled broch tower was invented in what is now Scotland. Even the pottery found inside brochs that resembled styles from southern Britain was a local version.
The first modern review of brochs (by Euan MacKie in 1965) did not, as some people think, suggest brochs were built by immigrants. Instead, MacKie proposed that a mix of a small number of immigrants and the native population of the Hebrides created brochs in the 1st century BCE, based on earlier, simpler forts. This idea contrasted with the view of Sir W. Lindsay Scott, who, following V. Gordon Childe (1935), argued that people from southwest England migrated to Atlantic Scotland.
MacKie's theory is no longer widely accepted, as archaeology has shifted in the 1970s from "diffusionist" ideas (which suggest outside influences) to theories that focus on development within Scotland itself. However, the limited number of radiocarbon dates for the original use of brochs (not their later use) still suggests most were built in the 1st centuries BCE and CE. A few may be older, such as the Old Scatness Broch in Shetland, where a sheep bone dated to between 390 and 200 BCE has been found.
Another broch, Crosskirk in Caithness, was once thought to be older than the 1st century BCE, but recent research suggests it was likely built during the 1st centuries BCE and CE.
Distribution
Brochs are mainly found in northern Scotland. The areas with the most brochs include Caithness, Sutherland, and the Northern Isles. Many brochs are also found in western Scotland and the Hebrides. While most brochs are in the northern Highlands and Islands, a few are located in the Borders, such as Edin's Hall Broch and Bow Castle Broch. Others are found along the west coast of Dumfries and Galloway and near Stirling. A drawing from around 1560 shows a broch near Annan Castle in Dumfries and Galloway. The small number of brochs in the south of Scotland remains unexplained.
Purposes
The original idea about brochs, believed by 19th-century experts, was that they were defensive structures used to protect communities and their animals. Some thought they were built by the Danes or Picts. From the 1930s to the 1960s, archaeologists like V. Gordon Childe and John Hamilton believed brochs were castles where local leaders controlled nearby people.
By the 1980s, the castle idea was no longer widely supported by Scottish archaeologists because there was not enough evidence to back it up. These archaeologists argued that brochs were not built for defense and may have instead been important homes that showed the wealth and power of families. However, there is still no strong evidence to support this view. The large number of brochs, sometimes in areas with poor land, also makes this idea difficult to prove.
Brochs often appear in groups and are found in many areas, which might suggest they had a defensive or offensive purpose. Some are built near steep cliffs and protected by natural or man-made barriers. For example, a broch at Burland near Gulberwick in Shetland is located on a cliff and surrounded by large ditches. Brochs are often placed at important locations, such as narrow waterways or near harbors. In Shetland, brochs sometimes appear on both sides of narrow water passages, like the Broch of Mousa, which faces another broch at Burraland in Sandwick. In Orkney, more than a dozen brochs are found on opposite sides of Eynhallow Sound, and many are near the entrances of Scapa Flow. In Sutherland, brochs are often placed along the edges of deep valleys. In 1956, John Stewart suggested that brochs in Shetland were forts used by a military group to watch over and protect the land and sea.
Some archaeologists now study broch sites individually, believing there was no single purpose for all brochs. Brochs vary in location, size, and likely importance depending on where they are found. For example, groups of brochs called "villages" are found in some parts of Orkney but not in the Western Isles.
Structures
Brochs typically have one entrance with bar-holes, door-checks, and lintels. Inside, there are mural cells, and a scarcement (a ledge) that may have been used for wooden lean-to buildings attached to the inner wall. A spiral staircase connects the inner and outer walls and links the galleries. Brochs range in size from five to fifteen meters (16 to 49 feet) in diameter, with walls up to three meters (9.8 feet) thick. Most walls survive only a few meters in height. Five broch towers have walls that are significantly taller: Dun Carloway on Lewis, Dun Telve and Dun Troddan in Glenelg, Mousa in Shetland, and Dun Dornaigil in Sutherland. These towers have walls over 6.5 meters (21 feet) high.
Mousa’s walls are the best-preserved and still stand 13 meters (43 feet) tall. It is unclear how many brochs originally had walls this high. A common feature is that the walls are galleried, meaning there is an open space between the outer and inner walls. These walls are connected by stone slabs, which may have served as steps to higher floors. It is normal for a small room, called a guard cell, to branch off from the entrance passage near the door. In some Shetland brochs, guard cells are located near large door-check stones. Although there was past debate, many archaeologists now agree that brochs were likely roofed with a conical timber frame covered in locally sourced thatch. Evidence for this is limited, though excavations at Dun Bharabhat on Lewis may support it. The main challenge remains finding sources of structural timber, such as bog wood or driftwood.
Few brochs on Orkney and Shetland have ground-floor cells. Most have scarcements (ledges) that may have supported a wooden first floor, as noted by George Low in Shetland in 1774. Excavations at Loch na Berie on Lewis suggest the possibility of a second floor, such as stairs leading upward. Some brochs, like Dun Dornaigil and Culswick in Shetland, have triangular lintels above their entrance doors.
Brochs were sometimes built near arable land and water sources, such as wells or springs. Others were located in remote areas, like Levenwick and Culswick in Shetland or Castle Cole in Sutherland. Many brochs are built near the sea, such as Carn Liath in Sutherland, or on islands within lochs, like Clickimin in Shetland.
About 20 broch sites in Orkney include small stone settlements surrounding the main tower. Examples are Howe near Stromness, Gurness Broch on Mainland, Midhowe on Rousay, and Lingro near Kirkwall (which was destroyed in the 1980s). "Broch village" sites exist in Caithness but are rare elsewhere.
Most brochs remain unexcavated. Broch construction likely ended around AD 100–200. Excavated brochs show they were used for centuries, with interiors often modified over time and through multiple phases of habitation and abandonment.
Heritage status
The Iron Age sites of Mousa, Old Scatness, and Jarlshof in Shetland are on the United Kingdom's Tentative List for possible UNESCO World Heritage Programme nominations. This list, published in July 2010, includes sites that might be nominated for inclusion in the future, possibly within the next 5 to 10 years.
New broch planned
The Caithness Broch Project began in 2013 as an experimental archaeology project to construct a broch using traditional methods like drystone walling. The goals of the project include helping to understand the function of brochs, keeping local skills such as drystone wall building alive, and drawing visitors to the area. As of 2022, the project had not yet secured a location, and the needed funding, estimated to be between £1 million and £3 million, had not been arranged.