Bu of Cairston

The Bu of Stromness is a curious ruin overlooking the Bay of Ireland on the southern side of the Orkney Mainland, which provides access to the inland lochs of Stenness and Harray. It is on low-lying land adjacent to a rocky foreshore, and is overlooked by a broch at the end of a ridge some 300 metres or so to the south-west. Access to the site, which is adjacent to working farm buildings, is along a single track road to the farm, and may be private.

The ruin consists of a squarish walled courtyard which once had two projecting round towers, and a series of buildings along the northern side, the westernmost of which has been interpreted as a small castle keep. The eastern wall and half of the southern wall has vanished completely, and the south-eastern round tower was discovered during excavation, lying on top of the earlier courtyard wall. It is conceivable that the Bu had its origins in the 12th century, and that it is a broad contemporary of Cubbie Roos Castle on Wyre, which is dated to the 1140s. The overall footprint of the Bu is similar, and the central square tower is also similar in size, although the walls are thinner. This assertion is based upon a section of the Orkneyingasaga which reads “They … went to see Earl Harald, who was with his fleet off Cairston. On the morning of Michaelmas Day, Harald and his men saw a longship coming towards them and, expecting trouble, they ran from their own ships into the fortress that used to stand there.” The saga then says that Earl Harald defended the fortress all day, leading his assailants to agree to a settlement. Whether the saga was referring to the Bu is questionable, but either the Bu or the broch could have been the location, since no other site which could have been seen as a fortress (the actual Norse word used is kastalann) is nearby.

Establishing a history of the site is, however, rather difficult. Cairston was held by a family of Gordons from at least the 1620s, and was then sold to a Mr Riddoch of Edinburgh who had lent him money for business ventures which had failed, perhaps in the latter 18th century. Whether the Gordons in question were, as tradition asserts, an offshoot of the Sutherland family is unknown. Of course, a significant factor in this is that Orkney remained part of the Kingdom of Norway until 1472, when it was taken by King James III in lieu of unpaid dowry money promised him by King Christian I.

In the absence of local royal control, the local Norse nobility of Orkney were responsible for building several stone castles in the 12th century, and it does on balance seem likely that a local notable was responsible for the erection of a stone courtyard at Cairston with a modest tower-keep. a pointer to the importance of Cairston might be that the “bordlands” of Orphir, the Earl’s estate where another “Bu” exists, was 18 pennylands worth, whereas Cairston was 27 pennylands. The lands of Cairston were therefore more valuable to the local lord than Orphir was to the earl, which may be reflected in the stronghold. The Bu was almost certainly repurposed and rebuilt in the 16th and 17th centuries, perhaps by the Gordons, as a mains farm, but presumably fell out of use following the lack of a resident, and the Riddochs had tenants who probably used the masonry to build a more modern farmhouse and buildings. Rather prosaically, the Bu itself was in use as a piggery in the 20th century, as can be seen in the image!

HES Canmore database entry