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Cronk ny Merriu is an excellent example of a Manx promontory fort and boasts a spectacular location.

Although no scientific dating has been undertaken, this site, and other Manx examples, have similarities with fortified headlands throughout England and Scotland constructed during the Iron Age.

The most obvious feature is the large, grass-covered bank, standing 3.5m high and 5m wide. The sheer scale of this led antiquaries to conclude that the site could only be a prehistoric burial mound, an assumption that was compounded by its name, which translates as ‘hill of the dead’. Only when the site was excavated was the bank shown to be a rampart constructed to separate the promontory from the rest of the cliff.

The promontory had previously been protected by a wooden stockade, and timber was also used, set vertically in the ground, to retain the earthen rampart that replaced it. The effectiveness of the rampart was increased by the creation of a ditch about 5m wide and over 1m deep. This has now largely silted up and only survives as a shallow depression at the foot of the outer face. The defensibility of the rampart was further augmented by a timber platform, or raised walkway. entry to the promontory was from the west side where the rampart is at its lowest, via an earthen or timber causeway.

The enclosed space seems small and is now largely filled by a later longhouse. During the Iron Age, there was probably a roundhouse here, but a combination of erosion of the cliff face and the construction of the longhouse has destroyed all but a few random postholes.

The longhouse measures 13.5m by 7.5m, with earthen walls 1.5m thick faced inside and out in stone. The walls originally stood to a height of around 1.5m, and probably supported a pitched roof. Two doorways are located directly opposite each other near the west end and low stone benches run along both of the long walls and the western gable. The excavations revealed little evidence of domestic activity, only rather basic remains of a hearth and no domestic rubbish. Whilst the form of the building is exactly what would be expected of a domestic viking longhouse, the excavated evidence suggests that it was not permanently occupied.

Several other Manx promontory forts have similar buildings within their ramparts, supporting the theory that existing promontory forts were reused as part of a ‘watch and ward’ system to protect the coastline and also to police beach markets. Several of the Iron Age forts were already in prime positions to guard landing places such as Port Grenaugh, and the construction of a building in which to shelter during inclement weather could explain the presence of the longhouse.


Text from 'A Guide to the Archaeological Sites of the Isle of Man' by Andrew Johnson and Allison Fox.

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