There is a strong local tradition on the Mizen, or Ivaha as I prefer to call it, that Dunmanus Castle is not the original. No – the first site for Donagh Mór O’Mahony’s Castle, the stories say, was in Knockeens, across Dunmanus Harbour from the present site. We set out to investigate.

This is the site, directly across the bay from Dunmanus Castle, and it’s what is labelled in the National Monuments records as a Cliff-Edge Fort. According to their definition that’s A penannular enclosure which utilises a cliff-edge to form one or more sides as an enclosing element. They date from the late Bronze Age up to the medieval period (c. 1800 BC – 16th century AD).

Perhaps the best known cliff-edge fort in Ireland is Dun Aonghasa on the Aran Islands (above) – it’s certainly the most spectacular. (Photo courtesy of Heritage Ireland) There are 20 examples of cliff-edge forts in Cork, of which only 6 are coastal, the rest are on ridges or steep slopes above rivers.

The problem is that some of these may genuinely be a specific type of fortification that uses the cliff-edge as an impregnable barrier – as promontory forts do, for example. Some of them, however, and this may apply to Knockeens, may have been circular ring forts, built on prominent locations to command views of land and sea, but which may have been eroded by sea-action until what is left is clinging on to the edge of a cliff. In the photo above, you can see the obvious erosion at Knockeens. Instead of a circular ring fort, what remains looks D-shaped.

In the 25″ OS map, done in the late 1800s, the site shows ‘Castle in Ruins’

There is plenty of evidence that the Irish clan chieftains built their castles on the sites of their former strongholds – ring forts, cashels and promontory forts (see my post on Three Castle Head, for example). If there was indeed a castle at Knockeens, there is not much evidence of it now, although there are tell-tale signs of some kind of masonry construction.

But whatever Knockeens was – a cliff-edge fort or a ring fort – it’s unusual and impressive. It consists now of a raised platform of earth, probably originally circular, and an outer wall (above). There may have been a radial wall once (see the map below), but it has been ploughed out and is no longer visible on the surface, although it shows up faintly in aerial photographs. There may have been a fosse, or ditch around the outer wall also – slight traces of this also remain.

The raised platform is an imposing spectacle. We approached it from the landward side and were unprepared for how tall it is. The interior sits high above the surrounding land – an extraordinary feat of engineering and one which could only be accomplished by a chieftain with the ability to command the labour of many people. 

If indeed most of it has been swept away by the sea, it is now, of course, only a portion of what it once was. It certainly accomplished several objectives: commanding the entrance to the sheltered harbour, allowing visibility up Dunmanus Bay, and being a dominating force on the landscape – in other words a high-status statement residence and fortification. 

The outer wall appears to have been stone-built or stone-lined (see image below), and it, or the raised platform may have had a palisade around the top – these were common in ring forts. 

Although we could not find a way to get at it from the stony beach below the cliff edge, we could just about make out, from Dunmanus Pier across the bay, a cross-section of stone wall where the platform meets the cliff. In one of the older maps, this is marked as a “Castle in Ruins” although all that is shown is a portion of wall. So there may well be a solid basis for the belief that this was the original site of Dunmanus Castle. 

Michael Healy tells it this way:

It is related locally that before he finally decided on Dunmanus as a site for his castle, Donagh Mór O’Mahony, early in the 15th century, had selected a site on the other side of the inlet and had set his men to work. While they were working a stranger came by and said that they should not build a castle in that place as the sea would come and wash it away. They did not see him again but the project was abandoned and Dunmanus was built on its present site.

The Castles of County Cork,

Michael J Carroll in repeats the assertion that this was intended as the site of the castle but introduces a nuance:

The workmen  noted, however, that the heavy winter seas rose up over the site. The project was abandoned and the stones removed for use in Dunmanus.

The Castles and Fortified Houses of West Cork,

I said at the beginning that there is a ‘strong local tradition’ that this was the original site. What we have learned to do in these cases is go to the Dúchas Folklore Collection, for the stories collected by schoolchildren in the 1930s – and there it was, written by an anonymous students in Kilcomane School (possibly Bridie Kennedy of Lissacaha). Here’s what she wrote:

When O’Mahoney was building his castles he had one for each of his sons. When he was building Dunmanus castle it was in the Knockeen’s side he laid the foundation. There is a part of it still remaining. It goes by the name of the old castle. A half fool one day was passing by and he saw them at work. He told O’Mahoney it was a foolish place to build a castle, that the swells of the ocean and the river from the mountain would eat the foundation from it.

O’Mahoney then asked him where would he build it and the fool showed him a rock at the opposite side of the river called the mount. Then O’Mahoney considered himself and found he had a mistake made, so he took the fool’s advice and built the biggest castle of all the rest on the mount.

https://www.duchas.ie/en/cbes/4921594/4882831/5147738

The sea stack above shows clear evidence of the amount of erosion that has happened over the centuries as well some kind of stone construction at the top level of the stack.

What are Amanda and Peter looking at? It’s a blow hole! Further evidence of how the sea can rage against this cliff.

So there you go – O’Mahony took the advice and built his castle where we see it today – the subject of a future post.

Please note that this site is on private land, used for cattle, and we were granted access by the kind permission of the owner. Our grateful thanks to him.