Castell Tremlyd

History of Deganwy Group. Castell Tremlyd Field Meet. 29.9.2011.

castell tremlyd 1

A research based reconstruction by Diane M Campbell Bannerman of how Castell

Tremlyd and Penlassoc may have appeared around 1500 when viewed from the ramparts

of Deganwy Castle.

Llandudno’s West Shore and the Great Orme in the Background.

Site Identification

The Cerrig Duon sea defence groyne is midway between Llandudno and Deganwy, on

the east side of the Conway river entrance. It occupies the site of Castell Tremlyd which

has been destroyed by erosion. The Castell first came to my notice when it was identified

on a slide of an 1835 Lewis Morris chart [Morris, L. 1835] being discussed in a lecture by

Dr. Cecil Jones. That there was no other information readily available on what was

apparently such an important structure was, from the first, something of a puzzle. Castell

Tremlyd had obviously occupied a strategic position at the mouth of the river Conwy

which would have influenced human activities, perhaps even as long ago as the Bronze


The later, more accurate, Lewis Morris charts [Morris, L. 1748] show a large fish weir

abutting the Castell. Its remains have been located 300m from the present shore line

indicating coastal recession of that amount since the early 18th century.

castell tremld 2

There was initial confusion over the name of the abutting fish weir depicted on the various

Lewis Morris charts. On the earliest chart it is named as Cored Wyddno and on later ones

as Gorad Faelgon. It is also known as the ‘Great weir of Gannow’ and ‘Goret Vailgon’

[Davies 1942 p4]. Aerial photographs revealed two adjacent fish weirs, the type 5 linear

shape of Cored Wyddno partially buried in mud, and the crescent shaped type 4 Gorad

Maelgwyn the western end of which disappeared into the sandbanks. I now feel that the

name ‘The Great Weir of Gannow’ was used to distinguish Goret Vailgon from Cored

Wyddno which could be described as ‘The Lesser Weir of Gannow’. For the sake of

clarity the fish weirs are hereafter referred to as Gorad Maelgwyn and Gorad Wyddno

[Bannerman & Jones. 1999]. [See Gorad Wyddno and Taliesin]

It also soon became clear from studying a 1695 chart by Capt G. Collins [Collins.1695]

that a village or Township immediately to the south of Castle Tremlyd had also been lost

to the sea.

The relevant details on the Chart are:

1. A prominent hill on a headland – both important navigational marks, Lewis Morris also

uses the headland as a mark but he identifies it as Castell Tremlyd. The hill also appears

on one of Morris’s navigational drawings.

castell tremlyd 3

As the drumlin hills in that area are some 20m in height and Castell Tremlyd Hill is

depicted by both Collins and Morris as being higher than the surrounding landscape it

seems fair to suggest that Castell Tremlyd stood on a hill some 30m high.

2. Three un-named houses and an inlet in the area just south of Castell Tremlyd. Collins

shows two other houses on the Creuddyn in the correct position for Deganwy, that is to

the north west of Deganwy Castle Hill.. On the western side of the River Conwy] he

shows only one house in Penmaenmawr and one in Abergwyngregyn. Apart that is from

Conwy Castle, walled town, a fish trap and fish house on Conwy Morfa]. This would

indicate that in the Tremlyd township there were three important houses while the

cottages and hovels of villains in this and other villages were not considered of


Professor A. Carr identifies the Tremlyd area as the site of the Township of Penlassoc

[Carr, A.1977]. Further to this there are records of three houses recorded in that place.

It was also realised that considerable land had also been lost from the opposite shore –

the western bank of the entrance to the Conwy River. Field work revealed the remains of

a fish weir in the position of a ‘Ware’ [a fish weir or fish trap] marked on the 1695 Collins

Chart and is hereafter referred to as Gorad Collins.

Close to the ‘Ware’ on the chart is shown a building. The 18th century Lewis Morris Charts

also show a building in the area described as a ‘Fish House’ This area was identified by

Rev. R.Williams in 1835 as being called ‘Cevnvro, the northern extremity of the marsh’,

the site of a long established pearl fishery [Williams 1835]. [See ‘Pearl Fishing’]


On Geological maps the low hills of the west shore are described as sand hills. After

walking the beach and examining the eroded shore a few times Dr. J.Wilkins visited the

site with me and agreed with my hypothesis that they were composed of Glacial Till. This

is an important point as sand hills are not a suitable site for a hill fort.

Between Tremlyd point and Deganwy, 2m below present high water mark, tree stumps

with their roots in blue/grey clay can be seen. At this site a section of tree trunk was found

eroding out of the clay. It appeared to have axe marks along its length but a retired local

plumber [Roberts D.K.] pointed out that blue clay was taken from the area for use in

jointing drainpipes. Examination of the radius of the marks suggested a spade had made

them, rather than an axe, supporting this suggestion. He also reported that antlers and

bones had been found during clay digging. A stream paeleochannel can be traced within

this deposit.

A Timeline for Castell Tremlyd


Although it is tempting and perhaps logical to speculate that the earthwork fort depicted

by Lewis Morris was originally Iron Age or even Bronze Age as things stand sadly it must

remain just speculation. But some clues may still remain below ground.

Castell Tremlyd the Roman Fort

In ‘Evolution of a Coastline’ Ashton refers to a paper read by Edward W. Cox in 1893 to

the Lancashire and Cheshire Historic Society which mentions Castell Tremlyd as having

been a Roman fort. [Unfortunately Ashton does not give the correct reference which leads

the researcher to a fruitless study of the proceedings of the Lancashire and Cheshire

Historic Society which are quite different to the proceedings of the Historic Society of

Lancashire and Cheshire wherein the paper is recorded.]

Cox describes Tremlyd as follows; `On the Conwy side of the Llandudno marsh stood the

Roman post of Castell Tremlyd and the British city of Dyganwy, which guarded the road

to the copper mines, and, possibly also a road to the Morfa Rhyianedd. The mines in the

Great Ormes Head were worked for copper by the Romans. Their fort is now in the sea,

and having been destroyed by erosion of the clay banks, it is utterly ruined, and its site is

only marked by a bank of loose stones and large boulders among which are found

Roman coins and fragments of tile.’ At this point Cox ends his description with the

frustrating words; `Fuller details of the traces of occupation must be left for another

opportunity.’ Whether this opportunity ever arose is not known but no further paper has

thus far come to light. [Cox, E.W. p.38]

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It is only too obvious that Cox had considerably more information on Castell Tremlyd,

which seems to have included details of artefacts found among the boulders, and that he

intended to prepare another paper on the subject. If such a document exists it could be

most valuable, for though much of what is contained in the paper quoted above is

conjecture presented as fact, actual references to artefacts found would be extremely


Ashton [Ashton W.1920] and others refer to low water track ways and track ways that

were once on dry land that are now below high water mark as will be discussed in `Roads

and tracks of the Morfa Rhianedd`. Castell Tremlyd would have occupied an important

position in this system guarding an important crossroads and ferry of the river Conwy. If it

was used by the Romans it would have been an important link in the chain of forts along

the coast. It was while researching into its possible association with the ferry I came to

realise that the area around the castle had been of some importance but had apparently

been known as Penlassoc from at least as early as 1350.

The Time of the Celtic Saints

Traditionally Maelgwyn Gwynedd the 6th century Welsh King who lived in what is now

known as the Deganwy Castle gave the Roman fort at Holyhead to St. Cybi. It is fact that

St. Cybi’s Church is built in a Roman fort, that the remains of a large fish trap known as

Gorad Maelgwyn exist and that Gorad Maelgwyn was in the ownership of St Cybi’s


It would seem that when Maelgwyn gave the land in Holyhead to St Cybi he also gave the

fish trap to his monastic college to finance its work. If this was the case Maelgwyn must

have had some concerns for his soul as it would appear that Gorad Maelgwyn was a very

valuable asset as will be discussed later. In about the year 1350 the annual rent for ‘The

Great Weir of Gannow’- Gorad Maelgwyn, was 40 shillings.

A Case in the Star Chamber

In 1541 Henry VIII granted the Ferries and Penlassoc to his Chamberlain, Sir Anthony

Weldon – a Knight of the Linen – and his wife in consideration of ‘his good and faithful

services’. However the grant gave rise to contention leading to claims and counter claims

being made as to who had right to what. The situation led to violence and outrages and

demands that the perpetrators be brought before the Star Chamber. The petitions tell of

men, ‘all fensably armed in Almaigne Ryvetts Jackes [German style leather jackets

studded with rivets] and other harneys with swyrds, bylles, bowes and arrowes’ who,

without just title or ‘Cause reasonable hath wrongfullye Entred into the same towne of

Penlassocke’ and prevented Sir Anthony’s wife going there to collect the ‘proffytts’

[Davies p.85]

It would seem that one Sir John Salisbury of Denbighshire, Chamberlain and Knight of the

Carpet, who was a somewhat autocratic man, had decided that the ‘proffytts’ of

Penlassoc and the Tal y cafn and Conwy ferries were his. He therefore directed his

servants, Morgan ap Ivan, John ap Ivan and ‘William of the chamber’ to go with Hugh of

the Peke and Eamond of the Peke to the town of Penlassoc to stop Lady Weldon from

collecting the dues and rents. Hugh of the Peke reinforced his band with his servants

Thomas ap Sion, Fluytt Meredith and Hugh Oakley, and ferrymen Richard ap Rhys and

Richard ap William along with ‘Diverse others unknown’.

It was these men who, wearing various types of armour, and armed with swords, bows,

and pikes, confronted Lady Weldon and her ‘servant’ Robert ap Hugh as they arrived at

Penlassoc ‘in a peaceable manner’. When Lady Weldon requested that they be allowed

to enter the town Salisbury’s bully boys ‘would give no ear unto them, but did beat and ill

treat them and drive them off with force’.

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Exactly what the outcome of the resulting trial in

the Star Chamber was is not known, but it seems that the Weldons were eventually

Lady Weldon and Robert ap Hugh about to be

attacked by Sir John Salisbury’s men at Penlassoc.

successful in regaining control. Their servant Robert ap Hugh, who was the owner of

Penrhyn Old Hall, later became Chief Constable and Member of Parliament. His loyalty to

his Mistress was apparently appreciated as he afterwards held the lucrative tenancy of

Penlassoc under very favourable terms.

A Port

There is one further reason why Penlassoc guarded by Castell Tremlyd could have been

of enormous importance in the past and that is as a port. Certainly to the sailors eye the

inlet shown on the Collins 1695 chart appears a snug little sheltered haven with possibly a

nice soft muddy area where boats could be safely beached. Immediately seaward from

Tremlyd point there also is more sea room than in the narrow channel upstream making

sailing easier. This would have been vital for vessels in the past whose sailing qualities

were sometimes not all that good. Another important consideration weighing against

navigating the Deganwy narrows is that, if either shore were held by an enemy, vessels

attempting a passage would be well within range of the Welsh longbow. Deganwy Castle

itself could well have used Penlassoc as a sea port.

Pearl Fishing

That pearls, normally associated with south sea islands, should number among the

treasures to be found in North Wales may seem a little bizarre but strong tradition has it

that even the Romans were attracted by the beauty of Conwy pearls. These pearls

however, came not from the oyster, but the freshwater mussels found in the upper

reaches of the Conwy and the marine blue muscles found at its mouth.

The main site of the industry was at Cefnfro, apparently now lost to the sea, on the

northern extremity of the Conwy Marsh – probably close to the present Conwy entrance

Perch Light. There is evidence that the Industry was also conducted around Tremlyd. A

by-product was boiled mussel flesh which was fed to large flocks of ducks, which would

themselves be a valuable source of food further adding to the worth of the area. Lewis

Morris reports in his 1748 list of commodities to be found at Conwy;

`This place was famous some time ago for pearl fishing; but now it is much neglected,

as it is all upon this coast, where the pearl muscle is found in great plenty.’ [Lewis Morris]

By the 1830’s the industry had apparently made something of a comeback as a

delightful contempory description of its methods and history shows in pearl fishery

described by the Rev.Robert Williams B.A. in 1835 :

`There are two kinds of muscles in the Conwy, from which pearls are obtained; mya

margaritifera, cragen y diluw, and the mytilus edulis, cragen las. Those of the former

species are procured high up river, above Trevriw, and pearls scarcely inferior to the

oriental ones are occasionally found in them. The pearl which Sir Richard Wynne of

Gwydir, chamberlain to Catherine, queen of Charles,11, presented to her majesty, was of

this kind, and it is said that it adorned the regal crown. These fine pearls are but seldom

met with, although the shells are common, and the search does not afford regular

employment. The shell is five inches and a half long, and two and a half broad. The other

variety, the cragen las, is found in abundance on the bar at the mouth of the river, and

great quantities of the muscles are daily gathered by numbers of industrious persons. At

ebb tide, the fishers, men, women, and children, may be observed busily collecting the

muscles, until they are driven back by the flood. They then carry the contents of their

sacks and baskets to Cevnvro, the northern extremity of the marsh, where the muscles

are boiled; for this operation there are large crochanau, or iron pots, placed in slight huts;

or rather pits, as they are almost buried in a vast heap of shells. The fish are picked out

and put into a tub, and stamped with the feet until they are reduced to a pulp; when, water

being poured in the animal matter floats, which is called solach, and is used as food for

ducks, while the sand, particles of stone, and the pearls, settle in the bottom. After

numerous washings, the sediment carefully collected and dried; and the pearls are then

taken to the agent, who pays for them so much an ounce; the price varies from one

shilling and sixpence to three shillings, according to the supply. Although the muscles are

not so abundant as formerly, it is surprising that the great quantities collected have not

exhausted the beds. The final destination of these pearls is completely hid in mystery,

and is only known to the gentleman who buys them up, the fortunate possessor of what is

a valuable secret [Williams, Rev. Robert B.A. 1835].

In 1897 certain articles relating to the pearl fisheries were displayed as part of the Welsh

Fisheries exhibit in the Yachting and Fisheries Exhibition at the Imperial Institute in

London. This is referred to in a report by Prof. Phillip J. White [ White, P.J. 1898. p41]. He

comments that the pearls ‘were either weighed in scales measured in ounce and half

ounce horn measures’. Some of these have survived and were recently displayed in

Llandudno Museum where I was kindly allowed to photograph them.

Prof. White also remarks that the remains of ‘one of the old kitchens where the mussels

were formerly boiled’ was located on a valuable building site and about to be destroyed

thus making it clear that although the main industry was at Cefnfro there were others

around the mouth of the estuary.

Fiona Richards has pointed out that in the 1851 census two Deganwy [?] women,

Susannah Parry and Mary Ann Jones, have pearling as their occupation. During `coast

defence’ work in the 1996/7 winter traces of a shell midden were exposed in the side of a

sand dune 1.5km west of Deganwy.

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Two Horn Pearl Measures

[Courtesy of Llandudno Museum

The 1820 R. Dawson map states; ‘Castell Tremlyd [no visible trace remaining]’, but what

was Dawson expecting to see? Remember this was an earthwork fort and perhaps the

bumps and hollows that can be seen on the shoreline are remnants of Castell Tremlyd.

Although the coastal recession at Tremlyd seems to have been halted it continued up

until quite recently. The 1891 25” map shows a triangulation pillar on Tremlyd point as

well as Castell Tremlyd Farm which was anecdotally lost to the sea in the early 20th

century. More research is needed!

Gorad Wyddno and The Legend of Taliesin

Although the story of Taliesin is a fanciful folk tale it has been associated with the Castell

Tremlyd site and as such it is relevant from a sociological perspective. In his 1814 book

the Reverend W.Bingley is quite definite that the fish weir Cored Wythno mentioned in the

Taliesin legend is the one at Tremlyd.

‘During part of the sixth century, Maelgwyn Gwynedd, prince of North Wales, kept his

court at Diganwy; and his brother Gwyddno Garanhir, [Gwyddno of the High Crown], the

Lord of Cantref Gwaelod, a hundred in Merionethshire, since overflowed by the sea,

resided also for some time in the neighbourhood. The latter had, near his residence, a

weir called Gored Wythno, Gwyddno’s Weir, which is even yet known by the same name,

and belongs to Sir Thomas Mostyn, as owner of the house of Bodscallon.’ [Bingley. p.81.]

There are other suggestions as to where Gwyddno Garanhirs fish trap was situated and

where the above legend took place. Bingley’s remarks do show that Cored Wythno at

Tremlyd, close to Maelgwyns Castle has a good claim and its own place in local legends.

Furthermore this account predates the Victorian ‘enhancement and dramatisation’ of

Welsh history.

The legend of Taliesin and Cored Wyddno

In brief, the legend tells how the child Gwion, who became Taliesin, had been set to stir a

magic cauldron for a year, in order to make a spell of beauty, wisdom, and second sight,

for Afag Ddu, the ugly and stupid son of the witch Queen Ceridwen. On the last day

Gwion splashed his finger with the boiling potion and in sucking it to relieve the pain,

received the full benefit of the spell, the remainder of the potion turned to poison. Gwion,

with his scarce necessary second sight, saw that Ceridwen was planning to kill him and

tried to escape, changing form as he did. But when he took on the form of a hare she

became a hound…. and so on through several changes, until he tried to hide as a grain of

corn in a barn. Ceridwen became a hen and after scratching around, found and ate him.

Instead of digesting him as she planned, the grain of corn entered her womb and she

bore him as a child. When he was born she found she was unable to kill him, so she put

him in a leather bag [ a coracle ?] and placed him in a river to take his chances. In this

way he came to be carried downstream to be caught in Gorad Wyddno. The fish trap was

owned by Gwyddno Garanhir. His son, Elphin, was rather extravagant and on one

occasion had to ask his father for the use of the weir for one night to repair his finances

by selling the catch of fish. In the morning the weir was found to be empty except for a

leather bag in which was found the child Taliesin, or ‘the one with the beautiful face’.

After being found by Elphin, he grew up very quickly, in a year or so he was fully grown,

becoming a great Bard who enchanted with his words, on one occasion rescuing the

hapless Elphin from his uncle Maelgwyn’s dungeon in Deganwy Castle.



The above is a précis of material collected during my research into the Castell Tremlyd

area. There is much more to be discovered about the area in both archive and field. The

comment by Edward W. Cox in 1893 that `Fuller details of the traces of [Roman]

occupation must be left for another opportunity.’ must be followed up by someone.

Perhaps the artefacts themselves may still come to light.

I have also been studying three other main coastal sites around Conwy Bay and the

Menai Straits focussing on coastal recession, relative sea level change and accretion.

This is now starting to allow observations and measurements to be correlated over the

whole area.

Coastal Recession

By carefully measuring coastal recession indicated by Fish Weirs and other man made

and natural features in many cases shown on old maps and charts it has been possible to

produce the following map on p.11 showing average rates of coastal recession over the

past 200 years.

N.V. Campbell Bannnerman

Special Thanks; Diane Campbell Bannerman, Dr. Cecil Jones, Bob Barnsdale, the staff of

Llandudno Library and many others.


Ashton W.1920 ‘The Evolution of a Coastline.’ Wm.Ashton & Sons Ltd. Grosvenor Works


Bannerman and Jones 1999. ‘Fish trap types: a component of the maritime cultural

landscape’ International Journal of Nautical Archaeology. 28.1: 70-84.

Bingley. Rev.W., F.L.S.1814. ‘North Wales’ 2nd. Ed. Printed for Longman, Hurst, Orme,

and Brown, Paternoster Row, London.

Collins Grenville Captain R.N. 1695 Hydrographic Chart of Conway Bay and the Menai


First published in 1693 it is probable that Captain Collins completed this Chart in 1683 or


Carr, A.1977 Map in ‘Atlas of Caernarvonshire’ 1977 Edited by T.M.Bassett & B.L.Davies.

Pub. Gwynedd Rural Council.

Cox, Edward W. ‘Traces of Submerged Lands on the Coasts of Lancashire, Cheshire and

North Wales’. the Historic Society of Lancashire and Cheshire. 1894.

Davies, H.R.1942 ‘The Conwy and Menai Ferries.’ The Board of Celtic Studies. University

of Wales Press, Cardiff.

Morris, L. 1735 ‘Cambria’s Coasting Pilot’

Morris, L. 1748 `Plans of Harbours, Bays and Roads in St. George’s Channel’

White, P.J. 1898 ‘Reports of the Puffin Island Biological Station’ Pub. Dept. of Zoology

University College of North Wales Bangor. Printer, Jarvis and Foster Bangor.

Williams, Rev. Robert.B.A. 1835 `The History and Antiquities of the Town of Aberconwy

and its Neighbourhood’. Christ Church, Oxford, Curate of Llangernyw. Printed by Thos.

Gee, Denbigh. 1835.


I had not visited the site of the fish weirs for some time and was quite surprised on the

evening of the visit that Gorad Wyddno was completely covered by sand. These intertidal

sites can change quite rapidly! The reasons can be complex but this points out the

importance of documenting changes and discoveries when they occur – it may be another

100 years before Gorad Wyddno is revealed again.

Copyright N.V. Campbell Bannerman 2011


additional researched work from N.V.Bannerman

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