If you're a hillfort hunter, West Penwith is not the best place to start. There aren't many, and they weren't necessarily built primarily for military purposes. They could be defended if need arose, though there was not a lot of need since Penwith is defended by its geography. Strongholds they were but, in our day, so are banks, warehouses and nuke stations.
Hill camps, inaccurately called hillforts, are enhanced, prominent hilltops dating from the late bronze age (after 1000 BCE) and the iron age (after 600 BCE and up to Roman times). Some were used earlier than this since many of them are special hilltop locations and, if you lived in ancient times, especially when they were warmer than today, you would have gravitated there too.
They are related to cliff sanctuaries (cliff castles), with similar periods of use and related aims.
Some of these sites go back to the neolithic - Chûn Castle and Trencrom Hill, for example. Nevertheless, most earthworks at hill camps derive from the iron age, so they're usually dated to the iron age.
Customarily hill camps are seen as defensive positions - an idea drummed in by post-Victorian archaeological orthodoxy and reinforced by the very names they've been given (hillforts, also cliff castles). There were most likely occasional feuds, raids, displays of male testosterone and drunken brawls in the iron age, but still, these sites were simply valued assets and, as such, they were protected. In West Cornwall there weren't many major threats necessitating defence - the cliffs, the area's remoteness and its distinct identity did much of the job.
Most hill and headland camps are located in beautiful, impressive, magical places, making them special, desirable residences and locations. A number of hill camps aren't necessarily in the best places for strategic defence, as such. But they were commanding places - gated communities for the powerful and their families.
In the iron age, society was by degrees more splintered, tribalised and, at times, insecure than a millennium before, with stronger concepts of hierarchy, territory and property. People drew lines around their central places and key assets, staking out their patch. So these places were protected, key assets, built because they were valued for a wider range of reasons than just defence.
Gateway into Chûn Castle
Encircling hill encampments are earth and stone banks, walls and ditches. Some camps had wooden stockades. Similarly, at the neck of many cliff sanctuaries are boundary banks, built in the iron age, even though many cliff sanctuaries started their careers in the neolithic.
In both cases, you get a distinct feeling you're crossing a threshold. In former times you would have had to enter through the proper entrance, which could be closed at dusk or when needed, so that entry and departure could be monitored.
There were practical reasons for building banks - protection against wolves, keeping children and livestock contained, providing wind-protection, and serving defensive purposes when necessary. There were also pride, wealth and status - hill camps were the residences of clan leaders, their entourages and their valuables, and below them lived the crofters and farmers.
A visit to Trencrom Hill, Chûn Castle, Bartinney or Castle an Dinas shows that they were hot properties. Their owners drew a magic circle around themselves, a ring-pass-not to deal with spirits, animals and strangers, to mark out safe space. This is ours, and our rules hold here.
Iron age society
St Michael's Mount from Trencrom Hill
People were tribal, and tribal lands extended quite far. But absolute sovereignty and despotic rule over territories was not the case: across Britain there was a notable set of pan-tribal laws and traditions, with a judiciary (the ovates), keepers of traditions and histories (the bards) and priest-philosophers (the druids) who held supervisory and advisory roles, welding Britain into an unified patchwork of domains without a constitutional framework but with rules, laws and customs nonetheless.
There was a philosophy of justice and fair allocation of resources: if families in tribes grew or shrank in size, periodic redistributions of land and houses would occur to accommodate such changes, and if there were extraordinary needs, the tribe would support those needs since the strength and welfare of the tribe as a whole were important.
Chiefs and local monarchs held resources on behalf of clan members and were generally accountable to them. It wasn't a perfect system and there were no doubt squabbles and injustices, but the British social system was noted and remarked on by outsiders. It had a common law system, and the British socio-political system of today has its roots in principles established in the iron age.
These were transitional times in which tribal and private rights were changing. Later in the iron age a money economy developed, and this 500ish year period saw an incremental shift from tribal toward more private conditions. But it was the coming of the Romans and later the Saxons who took this further, affecting Cornwall even though they didn't take it over.
Why hill camps?
Some hill camps served as meeting and council places, law courts, druid and artisan centres, trading and festival places. They were centres for farming, where livestock, seeds, tools and stores were kept - clan capital. Some were strongholds for protecting and smelting metals and valuables and for craft workshops, such as at Chûn Castle and Castle an Dinas.
Some were places for celebrating festivals (perhaps Caer Brân, Lesingey Round and Bartinney Castle) or for making trade (Castle an Dinas, St Michael's Mount, St Ives' Head, Lescudjak in Penzance and Carnsew near Hayle). They all varied in nature and purpose.
St Michael's Mount from Caer Brân
Only some hill camps were suited to big defensive showdowns. Trencrom Hill, Tregonning Hill (near Helston), St Michael's Mount and Chûn Castle were clearly defensible, but other so-called hillforts, such as Bartinney Castle, Caer Brân and even Castle an Dinas, originating in the bronze age, were more likely sacred enclosures for ceremonial and magical work.
In all three cases, the enclosing banks were completely round, and such a shape isn't the best for defensive purposes - they were round for more cosmological and geomantic purposes. All three sites were also located on relatively flattish areas, even though on hills with fine panoramas - with little height advantage for fighting against marauders.
Some ancient hills, such as Chapel Carn Brea, Sancreed Beacon, Watch Croft and Zennor Hill, together with the old neolithic tor enclosures of Carna Galva and Carn Kenidjack, were never made into hill camps. If iron age Britons were as conflicted and heroic as they're often portrayed, it might be expected they would be.
If hill camps were primarily defensive, one would expect more comprehensive coverage of the peninsula, with hill camps on such places as Rosewall Hill above St Ives, or in the southwest of the peninsula, or perhaps at Carn Kenidjack. It is more likely that the hill camps of Penwith were defended because they were there, and there for other purposes than strategic - more akin to medieval city walls than to distinctly military forts.
The hill camps were strongholds for people at the top of the clan hierarchies. They hosted the clan valuables, they were organisational and judicial centres, repositories for seeds, implements and stores, and they had some sacred functions. They would be defended but, most of the time, it wasn't necessary, since Penwith was easily defended as one peninsular landmass with a limited number of entry- and landing-points. St Michael's Mount and Trencrom Hill would, however, be strategically important during times of trouble - they were the gateposts to West Penwith from the east. Pass between them, and you needed the locals' assent.
Individual hill camps
Caer Brân, from Botrea
Caer Brân served as a central hub for Penwith. Elsewhere on this site it has been proposed that it might have been a kind of parliament and marketplace, with ceremonial significance too. Inside, one is visually insulated from the surrounding landscape, even though Caer Brân sits in a panoramic location. It wouldn't serve well for military purposes since you have to stand on the perimeter bank to see what's going on outside - easy to ambush.
This psychic insulation at Caer Brân makes it a kind of a Faraday Cage, a sealed-off place unaffected by the world around, where one's attention goes inward or upward but not outward. This suggests ceremonial-magical purposes or a role as a moot place or court. It could host 200 people easily. It is reachable from all parts of the peninsula, yet it is out of this world. It had three ring cairns inside it. Its current rather damaged state inside the surrounding banks doesn't do it justice.
Castle an Dinas has (or had) a similar insulated character, since it lies on a relatively flattish plateau overlooking Mount's Bay, with a wonderful view. It is more likely military than Caer Brân, probably involved in the tin trade - so there were security issues and valuables to guard. Militarily though it might not be the best place to fight from - Trencrom Hill or Lescudjack in Penzance would be better - but it would be a good place for mustering troops, keeping horses and supplies, were there a threat from the east or from Mount's Bay.
It would work well as a trading and market place, where Penwithians could meet outsiders and foreigners. It could also be a ceremonial place going back earlier than the iron age. Likely it was a mixture over time of all of these - it had a life-span of many centuries.
The path up to Chûn Castle from Chûn Quoit
Chûn Castle was undoubtedly a security stronghold, but not exactly military or strategic. Threats to it mainly came from raiders coming from the sea, perhaps from Ireland. It was a tin-industry centre, with stores, forges and craft workshops, so this place was wealthy and powerful.
It's a proud eyrie with a 360° panorama, for a grandiose lord who everyone knows is boss. But even in iron age times it had a heritage, having been a neolithic hill enclosure from at least the 3700s BCE, with its quoit just downhill from it. Just downhill the other way is Bosullow Trehyllis, an ancient settlement that no doubt serviced the hill camp.
On top of Trencrom Hill
Trencrom Hill is a delight and a very desirable residence - at least, in good weather. It's very defensible, with its own hilltop springwater source. Together with Chûn Castle, it's the only hill camp in Penwith where you can see both the north and south coasts.
Primarily it's a residence for the chief and his or her extended family, with a fine view of the domain - perhaps at least during the summer months. With St Michael's Mount it guards Penwith. It was a key beacon hill, in sight of Carn Brea near Redruth and, westwards, Castle an Dinas, southwards St Michael's Mount and southeastwards Godolphin Hill (for the Lizard) - well connected on the signalling internet between Penwith and the Scillies and upcountry.
Faughan Round near Paul is more a hill camp than a round, technically. It had two banks around it and a magnificent view over Mount's Bay. Not particularly good for defending itself, it nevertheless held command over Mount's Bay and would have been a good surveillance and mustering place, together with Lescudjack Castle, now incorporated into Penzance, home to many gardeners' allotments and surrounded by a housing estate. Lescudjack was probably a trading place - Penzance's out-of-town supermarkets lie below it, just to the east, to demonstrate the point.
Castle an Dinas
At hill camps and rounds, ancient site alignments pass sometimes to the centre, and sometimes they exactly tangent the perimeter. It's difficult to say why this is so - this is common across Britain. The banks around a hill camp represent the declaration of a force-field around the camp, significant as an energy-container. So there's clearly a point to this that is more than defensive.
In the case of the distinctly circular hill camps at Castle an Dinas, Caer Brân and Bartinney Castle, there could be a spinning effect that was sought after, to create a certain psychic vacuum or quiet-field inside. This might sound strange until one thinks of the quietness of a library, with its effect of encouraging focus of attention.
The Faraday Cage effect is important. To scientists and rationalists, what follows is distinctly inadmissable evidence. Yet if you are psychically sensitive, sitting inside such a space screens out interfering jangle and noise, and this facilitates benefits otherwise found in caves or the chambered cairns of earlier times.
It allows a capacity to gain a level of consciousness in which long-distance communication, healing, oracular work, invocation of deeper forces, focused ceremony or simple inner stillness are enhanced. This was arguably an important part of the purpose of these round quasi-henges, of which Penwith had three main ones - with Bartinney Castle looking west toward the Scillies and Castle an Dinas and Caer Brân looking east and south.
Rounds are circular lowland banked enclosures, often but not always containing the remains of settlements. Their main use seems to have been for homesteading and as enclosed farming hamlets or granges, presumably for prosperous farmers. Nowadays many of them have been ploughed over, appearing as a slightly raised circular bank or crop marks, though there are also cases of roundish field hedges following the boundaries of a round.
Some are located on quite strong alignments (such as Caergwydden Round and Faughan Round) and are definitely round in shape, suggesting sacred or geomantic thinking behind their design. So there is more to this than just protected farming strongholds and granges.
Kaer Round near St Erth Praze in East Penwith is on two significant alignments connected with West Penwith, suggesting it is more than a customary round, and probably older, and in existence for more reasons than farming. Several churches sit on rounds, including Gulval, St Erth and St Buryan, adopting iron age sites for later Christian purposes.
Lesingey and Faughan Rounds are more like hill camps than rounds. Most rounds were only mildly defensible, nevertheless offering protection to a hamlet or farm, keeping stock in and wild animals out. Again, it's the 'magic circle' idea, staking out 'our world'. Wind protection should not be ruled out as a reason for the building of their banks.
Most rounds were built etween 200 BCE and CE 100, though some have earlier origins. A few might be recycled bronze age sites. The position of some rounds on alignments connecting with much older sites suggests either that these sites might be older than we think, or that their builders decided to plug into older alignment systems.
There was something deliberate in the circularity of most rounds which is frequently forgotten - there's a feng shui aspect to it, even for quite functional rounds. The principles of bronze age geomancy seemed to be alive and well in the iron age, even if applied differently from before.