Castell Carndochan 2017 

During July Gwynedd Archaeological Trust will once again be working at Castell Carndorchan.

Castell Carndochan is a little-known 13th century castle of the Welsh Princes sitting on a rocky hill above Llanuwchllyn. It originally consisted of four towers and a wall running around the top of the hill. The outline of the castle is still visible but over the centuries everything has collapsed into large heaps of rubble. Gwynedd Archaeological Trust and Snowdonia National Park Authority have been working on a project, grant-aided by Cadw, aiming to stabilise the site and find out more about it.

Excavations in what was a large area of featureless rubble have discovered a previously unknown small half-round tower and the grand entrance to the castle. The newly discovered walls have been conserved and left exposed so that visitors can see parts of the medieval masonry. In the final year of the project excavations will continue on the small tower along with some minor investigations into the rest of the castle.

As part of outreach activities planned for the project, an open day will be held on Sunday 16th July. There will be three guided tours of the site led by the Trust archaeologist in charge of the project Dave Hopewell along with Rhys Mwyn. Minibuses will provide transport from Llanuwchllyn to the site and back, departing the pickup point at 10:30am , 2:00pm and 6:30pm . These tours are free but booking is essential. Contact Sian Evans / Bethan Jones for further details: 01248 366970. Minibus pick up point disclosed upon booking. The following week Ysgol OM Edwards will also be visiting the site where pupils will be given the chance to experience what it's like to be archaeologist.

The project has been made possible by grant assistance from Cadw. The Snowdonia National Park Authority has kindly provided financial assistance with the outreach components of the project.

Contact Sian Evans / Bethan Jones for further details: 01248 366970.


Castell Carndochan Excavations 2016

This year's work has concentrated on finishing work on the newly-discovered entrance into the castle. We had to stop last year because the outer end was buried beneath many tons of rubble. After four days of intensive clearance, we have uncovered the complete entrance passage which was not as badly collapsed as we feared. There was also an interesting surprise; the walls leading to the entrance converge on the outside and there appears to have been an arch over the outer end of the passageway. This collapsed many hundreds of years ago but fell into the entrance in one go and the remains are still understandable. The photo shows a view from the outside. The triangular key-stone with slate slabs to either side is clearly visible. The side of the entrance is just to the left of this; the stones under the remains of the arch have been placed there as a temporary support until it can be fully recorded next week. We also had two finds; a nice hand-made nail and a fragment of lead sheet. The lead may be from the roof of the big D-shaped tower.

Castell Carndochan - Week 2 - David Hopewell, site director

Mon-Tue 26 - 27th September

At the end of last week we were well ahead of schedule. Two days of torrential rain and gales have slowed things down considerably. The photo of Neil McGuinness sums it up!

On a positive note; more of the collapsed arch and entrance passage were found to survive under the rubble. We can now see that the entrance narrows at the outer end and the lower courses of the wall survive for almost all of the passage.


Wed 28th September

Still raining and blowing a gale, we need to get everything recorded but it's too wet to take photographs and we can only write on waterproof drawing film and that keeps blowing away. We have started a small assessment trench on the central square keep.


Thur-Fri 29th - 30th September

Finally, it has (mostly) stopped raining. There are a few odds and ends to finish off with the excavation and Neil and I have a lot of recording to do.

We decided to leave the semi-collapsed arch in place and rebury it. John Burman finished excavating the rest of the entrance passage. The original floor level consisted of a few slate slabs and a gravel surface. Was Llywelyn ap Gruffudd one of the last people to walk on this surface?

The square keep in the middle of the site has always been a bit of a mystery. It could have been the first element of the castle; a stand-alone tower like Dinas Emrys. We excavated a small area of it, looking at the outer and inner faces of the wall and a small area of the interior. It was built on the top of a very uneven lump of bedrock, so the floor must have been above the current height of the rubble. We found well-preserved, mortar-bonded wall standing to a height of about 0.8m. It had been built on the old ground surface with no foundations; the original turf level ran under the wall. There were no building regulations in the 13th century! The interior contained fire cracked stones and charcoal. It seems that this part of the castle had been destroyed by fire.

A coin was found in the last hour of the excavation. I was hoping for some accurate dating evidence. It however posed more questions than answers. After a quick clean it became clear that it was a copper jeton, a coin-like counter for use in calculations. Instead of the expected 13th century design we could see an orb, a feature of jetons produced in Nuremberg in the 16th and 17th centuries. How did this come to be lost on the site 300 years after the castle was assumed to have been abandoned?


Mon 3rd Oct

The long term plan for the site is to leave at least some of the newly-discovered walls exposed so that visitors can see and use the entrance. The mortar in the tops of the walls has washed out so any exposed stonework has to be repointed with lime mortar in order to stabilise it. Snowdonia National Park has arranged a program of consolidation and Alwyn Ellis and his team from Stonewyrcs, specialists in working in traditional materials, have started on site. The excavated areas will be partially backfilled in order to stabilise the site but as much of the walls as possible will be left exposed.

The excavation work was grant aided by Cadw and carried out by Gwynedd Archaeological Trust and a group of experienced volunteers. The consolidation works and outreach activity were directed by Snowdonia National Park and were funded by Cadw and the SNPA.

Thanks to Gwyn Roberts the owner of the site, Ian Halfpenny and Will Davies (Cadw) and John G Roberts, Naomi Jones and Jessica Enston (SNPA) and Neil McGuinness (GAT).

Special thanks to all who volunteered on the excavations and moved tons of rocks come rain or shine: John Burman, Beaver Hughes, David Elis-Williams, Jeff Marples, Rhys Mwyn and George Smith.


21st September 2016

Gwynedd Archaeological Trust has just started a further 2 weeks work at Castell Carndochan, a remote and rarely visited medieval masonry castle of the Welsh Princes, situated on the top of a prominent outcrop above Llanuwchllyn. We'll be finishing excavating around the area of the newly discovered entrance. We are working alongside the Snowdonia National Park Service who are overseeing the consolidation of exposed masonry. The work is grant-aided by Cadw, and we are also very grateful for all the help provided by Snowdonia National Park.

We'll keep you updated on the progress of the excavation on this page.


Castell Carndochan on S4C's 'Prynhawn Da'

On October 15th, S4C featured Castell Carndochan on their ‘Prynhawn Da' programme. The piece was filmed on the day of the ‘Open Doors' event that took place during this years' excavation. The feature can still be seen by following the link below, coverage begins in the 16th minute. Follow us on facebook and twitter to see more pictures of recent events at the site.


Conservation and excavation at Castell Carndochan, Llanuwchllyn

Gwynedd Archaeological trust has just finished 6 day's work with a team of volunteers on Castell Carndochan, a little known castle of the Welsh Princes near Llanuwchllyn. David Hopewell, site director, describes the site and the results of the excavations. The work was grant-aided by Cadw, and the Trust is grateful to Ian Halfpenny (Inspector of Ancient Monuments) for all his help, and we are also very grateful for all the help provided by Snowdonia National Park, through the services of its archaeologist John Roberts. Mike Garner, architect with Garner Southall Partnership, advised on the conservation needs of the site. The castle is a scheduled ancient monument.


Castell Carndochan Report in PDF format


The site, first impressions and initial recording

The site is a remote and rarely visited medieval masonry castle on the top of a prominent outcrop above Llanuwchllyn. Though impressively sited, the masonry remains, at first glance, are less impressive. However a more detailed examination reveals a defensive rock-cut ditch across the end of the promontory. The promontory itself is defended by a curtain wall around the perimeter, into which are built two possible towers. Foundations of a stone square tower lie in the centre of the castle. At the south-west end are the remains of a well-built large D-shaped tower. The masonry of this tower appears to be of a slightly different nature to the remainder of the castle.

We know little of the history of the site, as it is not mentioned in any medieval documentation, though the castle is usually thought to have been originally built in the early to mid-13th century, perhaps by Llywelyn ap Iorwerth. The internal square tower may once have stood on its own, as at Dinas Emrys, and the remainder of the site later constructed around it, perhaps in more than one phase. There is no evidence for continued occupation beyond 1283.

We produced a new plan of the site using the latest technology which enabled us to combine GPS surveying results with a detailed photographic record. A computer programme was used to produce a 3D model of the site from several hundred digital photographs. Details were added using old fashioned pencil and paper.

View of site from above generated from 3D model


The new plan of Castell Carndochan showing excavation trenches


Conservation work

The primary aim of the work was to conserve and protect areas of the site which were eroding through natural weathering. The worst area was in the D-shaped tower, where there was an area of collapse, and our first task was to investigate this and stabilise it in advance of the winter months, so that further conservation work can be carried out next year.

We carefully cleared the rubble from the worst collapse at the north-east end of the tower (Trench 1); it seemed that the wall had been undermined by an unauthorised excavation down to below the floor level sometime in the past. The good news was that even though part of the wall facing had collapsed the mortared core of the wall was still reasonably stable. The loose stone was used to build a buttress against the collapse in order to prevent further deterioration. The same process was carried out on a smaller area of collapse at the other end of the tower (Trench 2).

The wall after clearance, the wire was to stop loose stones falling on the archaeologists.

Assessment excavation

The central part of the castle is particularly ruinous. Scheduled Monument Consent was granted to clear the surface stone from three small areas in order to see if there was any significant archaeology left under the rubble. The intention was not to excavate any deeper at this stage.

Trench 3

This area consisted of a large heap of stones with no visible structure. It had been variously interpreted as a tower, an entrance or even part of an earlier hillfort. There were however no real clues on the surface, and we were delighted when removal of the rubble revealed well-preserved and stable mortared wall-facing and well laid mortared wall-core. We have interpreted the remains as two structures. The first structure is thought to be a second D-shaped tower with internal dimensions of 4.8m x 4.4m. The walls were up to 2.2 m thick.

Two lengths of wall showing that this was another D-shaped tower

The second structure, of which only a small part was revealed, is thought to represent one side of a rectangular structure with projected internal dimensions of 4m x 4m.

The corner of the rectangular building

Facing survived to a maximum of 0.5m above the clearance level and probing suggests at least a further 0.5m below further rubble. Neither structure was fully exposed.

Trench 4

Rubble was removed from the outer face of the central square keep revealing semi- collapsed possible wall-facing standing on a base of battered laid stone. The masonry was stable but partly collapsed and difficult to interpret. The most likely interpretation is that this was surviving wall core with the outer face collapsed. The lower part was built onto bedrock. A charcoal rich layer was observed beneath the rubble at the base of the masonry. This was not excavated but a small sample was taken. The upper wall of the keep appears to be 1.8m thick which appears to expand to 3m at the base.

The outer face of the keep was semi-collapsed and built on bedrock


Trench 5

A short length of the inner face of the curtain wall was cleared of rubble revealing well-preserved wall-facing standing to a height of 0.6m. This is the full height of the surviving masonry at this location.

The inner face of the curtain wall was very neatly built and well preserved although only to a height of 0.6m

It was noted that the mortar in trenches 3 and 4 contained cockle shells indicating a coastal origin (at least 30km away) for the lime. None were identified in the D shaped tower (trenches 1 and 2) suggesting both a different origin for the mortar and possibly a different phase of building. Mortar samples were collected for analysis.

After the new discoveries were recorded the excavations were carefully backfilled in order to protect the archaeology, returning the site to its original state…we even carefully replaced the grey lichen covered stones. It is intended that further conservation and excavation will be undertaken in 2015, but we are very pleased with the initial results of this years work.

Neil McGuiness drawing the end of the D-shaped tower

After backfilling: the site returned to its original state



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