These uniquely Scottish buildings, the Brochs were built between around 200BC and 100AD. Standing up to 15 m tall, these buildings were the largest iron age buildings in the UK and showed a complete mastery of the art of dry=stone wall building. They were round with a double wall, the inner wall being vertical and the outer wall tapering inwards. The top was probably capped with a thatched roof. The space between the walls contained rooms and galleries as well as a staircase which could have given access to the roof. The outer wall had no window openings and only one low door which opened into the inner space. This was divided into floors with the ground floor probably given over to livestock and the upper wooden floors to living space. The floors rested on stone ledges which can been seen on the inside wall. The Carloway Broch is the best preserved Broch in the Western Isles and one of the best in Scotland. It appears to have been in use (as a pottery) possibly as late at the 9th century AD and was still complete during the 18th century until it’s stones were mined for other buildings – the fate of most Brochs.
There is no firm conclusion for the purpose of the Brochs, possibly they were built for a variety of reasons. Firstly, they may have been built for defence, were the local population retired to it’s safety but without windows it would be hard to fight off attackers by throwing things down on them. In some cases Brochs were built in pairs which would lend credence to the idea of defending an area or inlet. Secondly, they were used as a look out point. They would be excellent for this but the location of some, in a loch for example, suggests not all would be suitable. Thirdly, they were built by wealthy people as a status symbol. Evidence of Mediterranean wine in some would support this idea but it seems unlikely that they would be built as close together as some have been found. So, no obvious conclusion, but maybe some were built for one reason and others for a second. You can ponder over this while stitching the kit.
Carloway Broch is now managed and maintained by Historic Environment Scotland.