Wales  >  North Wales  (Isle of Anglesey)


Beaumaris Castle was the last of Edward I’s great Welsh fortresses and was built to control the Isle of Anglesey. Although it was only completed long after Welsh resistance had been extinguished, it went on to play an important logistical role in the War of Three Kingdoms and remains a superb example of a castle built with concentric defences.





Beaumaris Castle was the last of the great fortresses built in Wales by Edward I. Earlier in his reign, he had fought two wars against Llywelyn ap Gruffudd, Prince of Wales whose stronghold was in Snowdonia in the north-west of the principality. In the first war, fought between 1276 and 1277, he had decisively defeated the Welsh Prince and confiscated all land to the east of the River Conwy. However, oppressive English rule led to a new conflict and in 1282 Edward again had to muster forces to occupy Wales. Gruffudd was killed at the Battle of Orewin Bridge in the opening stages of the war and English forces quickly overran lowland Wales forcing the rebels back into their Snowdonia redoubt. However, that relied upon supplies of food from the Isle of Anglesey, which was effectively the bread-basket for much of northern Wales, and accordingly the island was overrun by the English. With the Welsh defeated, Edward secured his conquest by building numerous castles to permanently encircle Snowdonia. Whilst some - Castell-y-Bere, Criccieth and Dolwyddelan - were modified Welsh built castles, he also commissioned three new fortresses at Caernarfon, Conwy and Harlech. A dedicated fortification on Anglesey was considered at this time but Caernarfon, on the mainland, was deemed sufficient. However, the situation changed in 1294 when a new Welsh rebellion, this time led by Madog ap Llywelyn, erupted.


Madog ap Llywelyn


In Autumn 1294 Madog ap Llywelyn rebelled against English rule. He was a descendant of the Princes of Gwynedd and his revolt soon gained traction aided by wide scale resentment against oppressive English rule and excessive taxation. The unfinished Caernarfon Castle was stormed by the rebels and burnt whilst the Sheriff of Anglesey was lynched. However, despite the loss of Caernarfon, the other fortresses built by Edward I proved their worth. Criccieth, Conwy and Harlech all held out and provided key bases to check the rebellion. In Spring 1295 Edward I launched a major amphibious landing on Anglesey, the centre of the insurgency, and devastated the major settlement at Llanfaes. The rebellion was crushed and by July 1295 Madog was in custody. However, the uprising had highlighted the folly of not having a fortress on Anglesey and within just a few weeks of landing on the island, Edward I had commissioned his chief engineer, Master James of St George, to build a new fortress.


The Castle


Work started on Beaumaris Castle in April 1295. The site chosen for the castle was near the Welsh town of Llanfaes in direct proximity to the Menai Strait, the stretch of water between Anglesey and the mainland. The site was unpopulated marshland when the castle builders started their work enabling Beaumaris Castle to be configured in an unrestricted concentric design (Caernarfon, Conwy and Harlech were also concentric but their shape was altered to fit the terrain on which they were built). The outer defence consisted of a moat, which was fed directly from the sea, which prevented undermining and provided a means of waste removal. The central defences consisted of an outer curtain wall augmented by circular towers. An Outer Gate provided access to a fortified dock ensuring the castle could always be resupplied by sea. The inner defences were the most substantial consisting of a tall curtain wall complete with six large towers and two massive gatehouse keeps.


Over 1,500 men were employed in the construction of Beaumaris Castle and progress proceeded apace; by the start of 1296 the structure already stood in excess of six metres tall. However, such construction was expensive and the same year the First War of Scottish Independence started. Although the Scots were swiftly defeated in the field, rebellion and uprisings continued forcing Edward to regularly campaign in the north. When the King sought to secure his new Scottish territories with castles, in the same manner as he did in Wales, he was forced to build his new structures in timber as he could no longer afford such lavish constructions such as Beaumaris. Linlithgow Castle for example was originally as large as Beaumaris but constructed solely from earth and timber. With such financial pressures, work on Beaumaris slowed considerably in Summer 1296 and thereafter virtually ceased. This left significant parts of the structure incomplete including the northern portion of the outer curtain wall and many of the buildings of the Inner Ward.


The Town


Concurrently with the construction of the castle, Beaumaris town was founded. This was established to the immediate south-west of the castle and the nearby existing Welsh town of Llanfaes was suppressed to prevent any competition with the new settlement. Beaumaris town thrived aided by its income from the Menai ferry and by 1305 it had become the largest borough in North Wales outstripping both Caernarfon and Conwy. Town walls were planned for the new settlement but, as work came to a halt on the castle, the plan was put on hold.


Later Medieval Period


Work on the castle resumed in 1306 after the constable, John of Metfield, petitioned Edward, Prince of Wales for funding. Over the next two decades, this funding enabled completion of the outer curtain wall. The fortress received semi-regular funding throughout the fourteenth century although it was never adequate and a survey in 1343 found the structure to be ruinous. Nevertheless, in 1381 it was able to defy a Scottish force that raided Anglesey. It was also able to resist Owain Glyndŵr in 1403 when he besieged the castle. Details of this action are sparse but records suggest Beaumaris held out for several months before falling to the rebels. It was recaptured by Irish mercenaries in 1405.


Beaumaris Town Walls


The Scottish raid of 1381 and the Glyndŵr revolt finally prompted the fortification of the town. Work started on the town walls around 1407 and enclosed a wedged shaped area extending westwards from the castle. It was a stone rampart, some two metres thick, fronted by a ditch. The wall remained intact until 1669 when portions were demolished to improve access and the remainder was removed during the eighteenth and nineteenth centuries.


Civil War


During the seventeenth century Civil War most of Wales was Royalist territory as was Anglesey. The island's remote location meant it played no part of the war until early 1646 when, with the Royalist cause on the verge of collapse, it became one of the last coastal locations through which the King could hope to import Irish troops. Richard Bulkeley was assigned as Governor and tasked with holding the castle but he was undermined by the local gentry and forced into surrendering to a Parliamentary force under Thomas Mytton. However in July 1648, during the Second Civil War, Buckley seized control of Beaumaris Castle and declared his renewed support for the King. He remained in possession until 2 October 1648 when he was compelled to surrender to a Parliamentary force. Thereafter the castle was slighted to prevent further military use. It passed into state care in 1926.





Ashbee, J.A (2017). Beaumaris Castle. CADW, Cardiff.

Davies, R.R (1987). Conquest, Coexistence and Change: Wales 1063-1415. Oxford.

Douglas, D.C and Rothwell, H (ed) (1975). English Historical Documents Vol 3 (1189-1327). Routledge, London.

Emery, A (1996). Greater Medieval Houses of England and Wales Vol. 2. Cambridge University Press, Cambridge.

Gravett, C (2007). Castles of Edward I in Wales 1277-1307. Osprey, Oxford.

Johnson, P (2006). Castles from the Air: An Aerial Portrait of Britain’s Finest Castles. Bloomsbury, London.

Kenyon, J (2010). The Medieval Castles of Wales. University of Wales Press, Cardiff.

King, C.D.J (1983). Castellarium anglicanum: an index and bibliography of the castles in England, Wales and the Islands.  Kraus International Publications.

Pettifer, A (2000). Welsh Castles: A Guide by Counties. Boydell Press, Woodbridge.

Purton, P.F (2009). A History of the Late Medieval Siege: 1200-1500. Boydell Press, Woodbridge.

Salter, Mike (1997). The Castles of North Wales. Malvern.

Taylor, A.J (2004). Beaumaris Castle. Cardiff.

Taylor, A.J (1987). The Beaumaris Castle Building Account. Cardiff.

What's There?

Beaumaris Castle, although never fully completed, is one of the most impressive fortifications built by Master James of St George. Its uncompromising concentric design is very impressive and much of the structure has remained unaltered since its initial construction.

Beaumaris Castle and Town Walls Layout. The castle was built to a concentric plan consisting of a moat, outer wall and inner wall. A fortified harbour provided the garrison with unrestricted access to the sea. The town was not fortified until 1407 following the Owain Glyndŵr rebellion.

Outer Gate and Fortified Dock. The castle's sustainability was ensured by a fortified dock directly adjacent to the Outer Gate. Note the masonry projecting from the rectangular tower next to the gate - these are surviving footings from the Town Wall. The break in its length was the location of the sluice that controlled the water level in the moat.

Outer Defences. The outer wall was protected by twelve round towers and had two gates. Over 300 arrow slits penetrated the walls. The moat was restored in the 1920s and would originally have been much wider.

Gunners' Walk. This wall projected out from the main defences enabling protection of the dock. A throwing machine, or other heavy projectile weapon, may have been installed.

Outer Ward. The gap between outer and inner defences formed the Outer Ward. If the outer defences were breached, this provided a killing ground in which attackers would be slaughtered.

North Gate. The grandest and largest structure in the castle, the North Gate was a lavish structure with a large hall and great chamber on the first floor.

South Gate. Originally planned to be as large and lavish as the northern entrance, the South Gate was never completed. However, its proximity to the Outer Gate meant it received a barbican in the early fourteenth century.

Conquest and Control. Edward I built and modified numerous castles in North Wales to isolate Snowdonia, redoubt of the Gwynedd Princes. Beaumaris was the last of these fortifications.

Outer Defences. The outer defences on the south-east side of the castle. The moat has been filled in on this side but various drains can be seen that originally discharged into it.

Getting There

Beaumaris Castle is located on the island of Anglesey just off the A545.  There is a large pay and display car park in the immediate vicinity of the castle.

Car Parking Option

B5109, LL58 8RA

53.265147N 4.087803W

Beaumaris Castle

LL58 8AP

53.264810N 4.089752W