Details

The monument includes a promontory fort. situated on a rocky headland between Halldrine and Porthmoina Coves. The fort survives as an irregularly-shaped enclosure defined by steep natural cliffs on all except the landward (south) side where the defences are provided by a drystone faced rampart of up 103m long and 2m high which retains a rubble-built bank of some 4m wide and 1.2m high. There are no visible traces of an outer ditch or internal occupation which leads to the general conclusion that either this was an occasional place of refuge or had permanent settlement only on a minor scale. The original central entrance is now blocked.
A stile (listed Grade II) standing within the monument is excluded from the scheduling, but the ground below is included.

Sources: HER:-
PastScape Monument No:-423566

Source: Historic England

Reasons for Scheduling

Promontory forts are a type of hillfort in which conspicuous naturally defended sites are adapted as enclosures by the construction of one or more earth or stone ramparts placed across the neck of a spur in order to divide it from the surrounding land. Coastal situations, using headlands defined by steep natural cliffs, are common while inland similar topographic settings defined by natural cliffs are also used. The ramparts and accompanying ditches formed the main artificial defence, but timber palisades may have been erected along the cliff edges. Access to the interior was generally provided by an entrance through the ramparts. The interior of the fort was used intensively for settlement and related activities, and evidence for timber- and stone- walled round houses can be expected, together with the remains of buildings used for storage and enclosures for animals. Promontory forts are generally Iron Age in date, most having been constructed and used between the sixth century BC and the mid-first century AD. They are broadly contemporary with other types of hillfort. They are regarded as settlements of high status, probably occupied on a permanent basis, and recent interpretations suggest that their construction and choice of location had as much to do with display as defence. Promontory forts are rare nationally with less than 100 recorded examples. They are important for understanding of the nature of social organisation in the later prehistoric period. The promontory fort called Bosigran Castle survives comparatively well and is unusual in having no apparent ditched defences. It will contain archaeological and environmental evidence relating to its construction, longevity, function, agricultural practices, territorial significance, settlement, strategic importance and overall landscape context.

Source: Historic England