Roundhouses - the precursors to the broch

From around 700BC, Iron Age Orcadians took to constructing strong, circular houses.

Today, archaeologists refer to these structures as "roundhouses" and believe the sturdy, stone dwellings were the prototypes of the later broch towers.

The earliest Orcadian roundhouse excavated to date was discovered at Quanterness, at the base of Wideford Hill, just outside Kirkwall. The Quanterness roundhouse was occupied from around 700BC until 200BC.

Another early roundhouse was excavated at Bu near Stromness. Dating from around 600BC, this was the home of a single farming family and featured a five-metre-thick outer wall. This seems to indicate that the structure was built with defence in mind, and provides a tantalising architectural link to the later brochs.

Staying in Stromness, another roundhouse was excavated at Howe, on the hill between Stromness and the Stenness loch. This structure was also apparently built for defensive purposes, having walls and ditches surrounding the main dwelling.

But although defence may have played a part in the development of the roundhouse, like the later brochs, they may simply have been an expression of an individual's, or family's, social standing.

In contrast to the semi-subterranean dwellings of earlier eras, the roundhouse towered above the surrounding landscape, perhaps reminding the locals of the power of the inhabitants and visually reinforcing their place in society.

But whatever their purpose, excavations of roundhouse sites have allowed archaeologists to show that the complexity and scale of the structures continued to develop until they became the massive fortified broch towers, the remains of which now dot the northern landscape.

The layout of a broch