Beaumaris Castle, located in the town of the same name on the Isle of Anglesey in Wales, was built as part of Edward I's campaign to conquer the north of Wales after 1282. Plans were probably first made to construct the castle in 1284, but this was delayed due to lack of funds and work only began in 1295 following the Madog ap Llywelyn uprising. A substantial workforce was employed in the initial years under the direction of James of St George. Edward's invasion of Scotland soon diverted funding from the project, however, and work stopped, only recommencing after an invasion scare in 1306. When work finally ceased around 1330 a total of £15,000 had been spent, a huge sum for the period, but the castle remained incomplete.
Beaumaris Castle was taken by Welsh forces in 1403 during the Owain Glyndŵr rebellion, but recaptured by royal forces in 1405. Following the outbreak of the English Civil War in 1642, the castle was held by forces loyal to Charles I, holding out until 1646 when it surrendered to the Parliamentary armies. Despite forming part of a local royalist rebellion in 1648 the castle escaped slighting and was garrisoned by Parliament, but fell into ruin around 1660, eventually forming part of a local stately home and park in the 19th century. In the 21st century the ruined castle is managed by Cadw as a tourist attraction.
Historian Arnold Taylor described Beaumaris Castle as Britain's "most perfect example of symmetrical concentric planning". The fortification is built of local stone, with a moated outer ward guarded by twelve towers and two gatehouses, overlooked by an inner ward with two large, D-shaped gatehouses and six massive towers. The inner ward was designed to contain ranges of domestic buildings and accommodation able to support two major households. The south gate could be reached by ship, allowing the castle to be directly supplied by sea. UNESCO considers Beaumaris to be one of "the finest examples of late 13th century and early 14th century military architecture in Europe", and it is classed as a World Heritage site.
In 1400 a revolt broke out in North Wales against English rule, led by Owain Glyndŵr. Beaumaris Castle was placed under siege and captured by the rebels in 1403, being retaken by royal forces in 1405. The castle was ill-maintained and fell into disrepair and by 1534, when Roland de Velville was the castle constable, rain was leaking into most of the rooms. In 1539 a report complained that it was protected by an arsenal of only eight or ten small guns and forty bows, which the castle's new constable, Richard Bulkeley, considered to be completely inadequate for protecting the fortress against a potential Scottish attack. Matters worsened and by 1609 the castle was classed as "utterlie decayed".
The English Civil War broke out in 1642 between the Royalist supporters of Charles I and the supporters of Parliament. Beaumaris Castle was a strategic location in the war, as it controlled part of the route between the king's bases in Ireland and his operations in England. Thomas Bulkeley, whose family had been involved in the management of the castle for several centuries, held Beaumaris for the king and may have spent around £3,000 improving its defences. By 1646, however, Parliament had defeated the royal armies and the castle was surrendered by Colonel Richard Bulkeley in June. Anglesey revolted against Parliament again in 1648, and Beaumaris was briefly reoccupied by royalist forces, surrendering for a second time in October that year.
After the war many castles were slighted, damaged to put them beyond military use, but Parliament was concerned about the threat of a royalist invasion from Scotland and Beaumaris was spared. Colonel John Jones became the castle governor and a garrison was installed inside, at a cost of £1,703 a year. When Charles II returned to the throne in 1660 and restored the Bulkeley family as castle constables, Beaumaris appears to have been stripped of its valuable lead and remaining resources, including the roofs.
Lord Thomas Bulkeley bought the castle from the Crown in 1807 for £735, incorporating it into the park that surrounded his local residence, Baron Hill. By then the castles of North Wales had become attractive locations for visiting painters and travellers, who considered the ivy-clad ruins romantic. Although not as popular as other sites in the region, Beaumaris formed part of this trend and was visited by the future Queen Victoria in 1832 for an Eisteddfod festival and it was painted by J. M. W. Turner in 1835. Some of the castle's stones may have been reused in 1829 to build the nearby Beaumaris Gaol.
In 1925 Richard Williams-Bulkeley gave Beaumaris to the Commissioners of Works, who then carried out a large scale restoration programme, stripping back the vegetation, digging out the moat and repairing the stonework. In 1950 the castle, considered by the authorities to be "one of the outstanding Edwardian medieval castles of Wales", was designated as a Grade I listed building – the highest grade of listing, protecting buildings of "exceptional, usually national, interest".
Beaumaris was declared part of the Castles and Town Walls of King Edward in Gwynedd World Heritage site in 1986, UNESCO considering it one of "the finest examples of late 13th century and early 14th century military architecture in Europe". In the 21st century Beaumaris Castle is managed by Cadw, the Welsh Assembly Government's agency for historic monuments, as a tourist attraction, with 75,000 visitors during the 2007–08 financial year. The castle requires ongoing maintenance and repairs cost £58,000 over the 2002–03 financial year.