Before his more famous war for control of Scotland, Edward I Longshanks waged a war for control of Wales. In order to cement English control over the troublesome Welsh, Edward built a series of castles in northern Wales, sometimes referred to as the Ring of Iron. In this article, we will examine four of the greatest of these castles, which together form a UNESCO World Heritage Site.1. Caernarfon: Echoes of RomePhotograph of Caernarfon Castle exterior. Source: Phillip Johnson, 2006Although not the largest Welsh Castlethat honor belongs to Caerphilly Castle in the southCaernarfon is definitely one of the most impressive. Indeed, its design was meant to impress the local population as much as to dominate them. When work began on the fortifications in 1283 bones were discovered in the area which were thought to be those of Magnus Maximus, believed to be a grandson of Constantine, the first Christian Roman emperor. The area of Caernarfon was already linked to Rome in local folklore as attested to in the Mabinogion, a medieval Welsh text.Edward and his master architect, James of St. George, took full advantage of these imperial associations, modeling the walls and towers on those of Constantinople, the capital of the Eastern Roman Empire, and adorning the greatest of Caernarfons towers with eaglesa connection to imperial Rome which would be lost on no one. The entire appearance of the castle called out in no uncertain terms You have been conquered to the local Welsh in the area.The castle and town walls of Caernarfon were conceived of from the beginning of construction as a unified whole, reminiscent of Carcassonne in southern France, which Edward may well have seen in his earlier years. The castle was situated with its south wall facing the River Seiont at the point where it empties into the Menai Strait, with the city walls springing out northward from the northeastern and northwestern towers and coming together at a point near the River Cadnant.The castles defenses consisted of a gatehouse and a series of polygonal towers which, in imitation of Constantinople, differed from the round towers preferred in the rest of Edwards castles. Seen from above the castle creates a sort of angular figure eight, which was originally divided into an upper ward (east of the gatehouse) and a lower ward (west of the gatehouse).Photograph of Caernarfon Castle interior. Source: Phillip JohnsonWhat Caernarfon is perhaps best known for has to do with the British royal title, Prince/Princess of Wales. In April of 1284, when construction on the castle was still ongoing, the future King Edward II was born at Caernarfon. In 1301 Edward I bestowed upon him the title, Prince of Wales, thus making him the highest authority in Wales after the king himself. Legend has it that this act was the fulfillment of a promise to the Welsh to give them a prince born in Wales who spoke no English, but this story was not recorded until the 16th century. Whether the legend holds any truth or not, the fact remains that most heirs apparent to the British throne ever since have held the title.On July 1st, 1969, the current king Charles III was invested as Prince of Wales at Caernarfon before a crowd of 4,000 guests, with an estimated 19 million further Britons watching along at home on television. However, William, the current Prince of Wales, declined to hold a similar investiture ceremony.2. Conwy: Towers to Project PowerPhotograph of Conwy Castle from the town wall. Source: Phillip Johnson, 2013Begun only a few months before Caernarfon, Conwy is just as impressive a castle, but for different reasons. While Conwy lacks the imperial Roman connections and perhaps the elegance of Caernarfon, it has Caernarfon beat hands down for sheer intimidation. Built upon a natural rocky outcropping, the castles defenses are essentially straightforward, consisting of eight almost identical 70-foot-tall round towers, massive curtain walls, and a gate with a barbican. Four of the eight towers, those nearest the river Conwy, include turrets as an additional feature, most likely as they overlook the inner ward, where the royal apartments were located. Seeming to spring straight up out of the rock it was built upon, Conwy is a truly daunting sight to behold from ground level.Unlike Caernarfon, where construction work was still ongoing when the Welsh revolt broke out in 1294, Conwy was completed in a mere four yearsan astonishing rate of construction for the time. As at Caernarfon, the castle and walled town were planned as a unified whole and Conwy was intended from the beginning to serve as the administrative center for northern Wales. Edward even took the unusual step of relocating the abbey of Aberconwy nearly ten miles away in order to make way for construction.The town walls at Conwy, even more so than at Caernarfon, are essentially an extension of the castle itself. With 21 regularly spaced towers and three fortified gates, the town walls at Conwy are truly a marvel of medieval defensive architecture and are one of the best-preserved examples in Europe.Photograph of Conwy Castle interior. Source: Phillip Johnson, 2006Perhaps due to its tremendously imposing appearance, Conwy Castle remained free from attack from the time of its completion in 1287 until 1401 during the Welsh revolt under Owain Glyn Dwr. Several records from the 14th century mention the deteriorating state of repairs in the castle, but this did not prevent it from seeing its share of excitement.In 1399, Richard II sought refuge from Henry Bolingbroke (later King Henry IV) at Conwy, and it was after leaving the castle that he was ambushed and captured, leading to his imprisonment and ultimately his death at Pontefract Castle. Then in 1401 two cousins of the Welsh rebel leader Owain Glyn Dwr managed to take Conwy Castle, according to one source through trickery while the garrison was at prayer. They were able to hold the castle for several months, which served as an inspiration to other Welsh rebels against English rule.3. Harlech: Holding the High GroundPhotograph of Harlech Castle exterior, by Peter Broster. Source: Wikimedia CommonsBegun the same year as Caernarfon and Conwy (1283), Harlech is another outstanding testament to both the determination of Edward I to dominate northern Wales and to the genius of his master architect, James of St. George. Perched upon a rocky promontory, overlooking the sea, and with the mountains of Snowdonia behind it, Harlech occupies perhaps the most picturesque location of all Welsh castles as well as one the most defensible. The sea no longer reaches as close to the castle as it once didoriginally Harlech could be supplied by sea making it nearly impossible to starve out the defenders without a naval blockade, which the Welsh were never in a position to accomplish.Harlechs design took full advantage of the areas topography as well as the latest advances in military defensive architecture. Merely approaching the castle atop its giant rock would be a literal uphill battle. Harlech is then defended by concentric walls, stout round towers at all four corners, and an impressive two-towered gatehouse. The symmetry of the design is nearly perfect, foreshadowing the design of Beaumaris castle in the following decade (see below).By 1289, Harlech was mostly completed, and it was put to the test during the Welsh uprising in 1294. Its ability to be supplied by sea proved decisive and the rebels were unable to take the fortress. However, the walls protecting Harlechs sea access were further strengthened to ensure that this vital lifeline was completely protected.Photograph of the gatehouse at Harlech Castle. Source: Phillip Johnson, 2013Like Conwy, Harlech saw its share of action long after the Welsh wars of Edward I were over. The forces of Owain Glyn Dwr took Harlech in 1404 and held it until 1409. When Harlech fell once again to the English, under the command of Henry of Monmouth, Prince of Wales, and future King Henry V of Agincourt fame, the castle and its rebellious Welsh defenders were subjected to fierce cannon fire. Legend has it that one of these cannons was called the Kings Daughter, but apparently it did not survive the siege, having burst at some point during a cannonade.Later in the 15th century, during the Wars of the Roses, Harlech was again at the center of the action. As a stronghold of Lancastrian power, it proved to be an increasingly irritating thorn in the side of the Yorkist King Edward IV. In 1468, King Edward sent an army of 7,000-10,000 men to take Harlech. The castle could not withstand the numbers and firepower of the Yorkist army and fell in less than a month. Tradition has it that this siege inspired the Welsh song, Men of Harlech.4. Beaumaris: Unfinished PerfectionPhotograph of Beaumaris Castle exterior. Source: Phillip Johnson, 2013Beaumaris Castle (roughly fair marsh in Anglo-Norman) is one of the best, if not the best, examples of symmetry and concentric defenses of any medieval castle in Europe. Begun in 1295, in response to the revolt that broke out the previous year, this was the last Welsh castle to be built under the rule of Edward I. However, despite construction work continuing off and on for several decades, Beaumaris never attained the full scope envisioned by its architect, James of St. George, and remains today an unfinished template, but with a plan so well-articulated that the imagination can easily fill in the missing bits.Unlike the other three Welsh castles discussed here, Beaumaris was placed on a site with no natural features either to take advantage of or to work around, hence the perfect symmetry of the design. Its defenses consisted of a moat, concentric walls, 18 towers, and two stout gatehouses, and it was originally suppliable by sea. Construction work on the castle proceeded relatively quickly, however, money to pay for building materials and laborers began to run out in 1296, and work appears to have ceased completely by 1298. This lack of funds was partly due to Edwards costly wars in Scotland. In 1306, construction work began anew and continued off and on until 1330, by which time the castle had reached the unfinished form we see today.Photograph of Beaumaris Castle interior. Source: Phillip Johnson, 2013Largely due to its unfinished condition, Beaumaris saw little military action over the centuries. It featured briefly in the revolt of Owain Glyn Dwr at the beginning of the 15th century, falling into Welsh hands before being quickly retaken by the English. It was also used by royalist forces loyal to Charles I during the English Civil War of the mid-17th century. Along with Conwy, the fortifications received some repair work and Beaumaris was used as a sort of staging area for supplies coming from Ireland. However, Parliaments ultimate victory led to the surrender of the castle in 1646. This was the last military use Beaumaris would see.The Four Welsh Castles TodayEdward Longshanks, by Renold Elstrack, 1618, via the British MuseumCaernarfon, Conwy, Harlech, and Beaumaris can all be visited year-round and are well worth seeing. The four castles are administered by CADW, the historic environment service of the Welsh government. Although all four castles are fairly close to each other (the furthest distance is between Conwy and Harlech, which is just over an hours drive) it is not recommended to try to visit all four on the same day. A thorough exploration of each castle requires 2-3 hours, and the author would advise spending as much time as possible investigating every nook and cranny. Each of these castles is a medieval history lovers dream come true.