Beaumaris Castle, located  on the Isle of Anglesey in Wales, was built as part of King Edward I’s campaign to conquer the north of Wales. It was designed by James of St. George and was begun in 1295, but never completed. Beaumaris is part of the World Heritage site.

Beaumaris Castle was positioned to face the royal llys at Abergwyngregyn on the opposite shore of the Menai Strait and was intended, along with Conwy Castle and Caernarfon Castle  at either end of the Menai Strait, to overshadow the Welsh Royal home and centre of resistance to the English forces. Its constable from 1509 to 1535 was Sir Roland de Velville, a reputed son of King Henry VII of England.

Beaumaris derives from the Anglo-Norman Beau Mareys meaning “beautiful marsh”.

English rule in Wales was established after King Edward I of England conquered the country. Provisions for the governance of Wales were set out in the Statute of Rhuddlan, enacted on 3 March 1284. It was divided into counties and shires, emulating how England was governed. The island of Anglesey constituted its own county. The new castles of Harlech  and Caernarfon became administrative centres, and the latter was effectively the capital of north Wales.

While the decision to build Beaumaris Castle may have been taken early, 1283 has been suggested, building resources at the time were almost at full capacity, with the foundation of Harlech, Caernarfon, and Conwy, and repairs at a number of other castles, all funded by Edward I.

The site chosen for Anglesey’s castle was about 1 mile (1.6 km) from the town of Llanfaes. As well as being the island’s main trading port, Llanfaes was the wealthiest borough in Wales and largest in terms of population. The important town was roughly midway between Conwy and Caernarfon. The intention was to build a walled town adjacent to Beaumaris Castle, so to allow it to prosper the inhabitants of Llanfaer were moved some 12 miles (19 km) southwest, where a settlement by the name of Newborough was created. In the autumn of 1294 the Welsh rebelled against English rule. Edward I defeated the Welsh in the ensuing campaign, and after the rebellion had been suppressed he began work on Beaumaris Castle. With Conwy and Harlech complete by the end of the 1280s, and Caernarfon well under way, resources could be directed to building Beaumaris.

The construction of Beaumaris Castle was overseen by Master James of St. George. Under Edward I, James had held the title of “master oif the king’s works in Wales”, reflecting the responsibility he had in their construction and design. From 1295, Beaumaris became his primary responsibility and more frequently he was given the title “magister operacionum de Bello Marisco”  Pipe rolls are continuous records of royal expenditures, and the roll from the seven year of Edward II contains a summary of the work in the first three years at Beaumaris. It contains some of the most detailed information on the early stages of castle construction.

Beaumaris Castle was the last of Edward the I’s fortresses in North Wales. Work started in 1295 and continued for 35 years, with over 3,500 workmen employed at the peak of construction. Finances and material ran out when King Edward turned his attentions towards Scotland, and the castle was not completed, although an impressive £15,000 was expended on its construction.