Inscribed in 1986
The decision of King Edward I of England, announced on 17 November 1276, to go against Llywelyn, prince of Wales, as a rebel and a disturber of his peace, resulted in a programme of castle building in north Wales of the first magnitude. During the next twenty years no fewer than eight new castles were begun by Edward and carried far towards completion.
Of the eight new castles the finest were Beaumaris, Caernarfon, Conwy and Harlech, all on coastal sites in north-west Wales. Two of these, Caernarfon and Conwy, were associated with new towns enclosed within massive walls built at the same time as the castles. These four great castles and two sets of town walls collectively make up the World Heritage site. All were begun and substantially completed within the period 1283 to 1330, though much of the work was carried out before 1300.
The castles at Harlech and Beaumaris were built to a concentric plan, with features common to both but adapted to suit the differing site conditions - level ground at Beaumaris and a massive rocky promontory at Harlech. The essential feature in each case was an inner enclosure confined within a lofty curtain wall, entered through a heavily defended gatehouse and strengthened with a series of projecting towers. Outside was a series of outer defences, modified according to the nature of the site and including an outer ward, an outer curtain wall and a deep ditch, dry in the case of Harlech and water-filled in the case of Beaumaris.
By contrast, the castles at Caernarfon and Conwy were elongated fortresses, each with a pair of adjacent wards surrounded by a high curtain wall with projecting towers. The defences were extended by a massive wall encircling the town, again with twin-towered gatehouses at the principal points of entry and projecting towers at regular intervals.
The castles were not designed simply as garrison strongholds; they were also seats of government and symbols of power. The driving force behind the project was the king himself. Organising and direction during the crucial years were the responsibility of the Savoyard, James of St George. The result, both individually and collectively, is the finest surviving example of late thirteenth-century military architecture in Europe, including at Beaumaris the near-perfect concentric castle; at Caernarfon the embodiment of power; at Conwy a castle sited to dominate a vital river crossing; and at Harlech, poised on its crag against the mountain backdrop of Snowdonia, the medieval castle at its most picturesque.
The castles all played their part in the subsequent history of the country, but in general, due to improved relations between England and Wales, their story was one of long periods of neglect with occasional spells of intense activity such as the early fifteenth century Glyndwr uprising and later when they were held for king against parliament in the Civil War in the seventeenth century. As a result they have survived largely intact.
What has also survived is much of the contemporary documentation which provides a human dimension to illuminate the story elsewhere preserved in stone. We know in detail who worked on the castles, where they came from (virtually all over England and Wales) and what they were paid.
Cadw is committed to improving access and interpretation at Beaumaris, Caernarfon, Conwy and Harlech. Details of new work will be posted on the website.
There is more information about the castles and town walls of Edward I in Gwynedd on the UNESCO website, including the statement of Outstanding Universal Value.