Grosmont Castle

Grosmont Castle is a ruined medieval castle in the village of Grosmont, in Monmouthshire, above the valley of the River Monnow. The Welsh names of the village are Y Grysmwnt and Rhosllwyn. The castle name is explained as gros mont, French for a big hill. It stands where the Monnow passes between Graig Syfyrddin, also called Edmund's Tump and possibly named for Edmund Crouchback, and the Garway and Orcop hills.

With Skenfrith Castle and White Castle it formed the lordship known as the Three Castles, held together to watch the route from Wales toward Hereford. The stone that remains is the local Old Red Sandstone, also described as the local red sandstone. The castle is ruined, open to the public, and in the care of the state. There are circumstantial indications that the village may have begun as an Iron Age camp, and the settlement that grew beside the castle was a Norman planted town.

The first fortification followed the Norman conquest of England in 1066. William the Conqueror made William FitzOsbern, 1st Earl of Hereford, and the new earl took Monmouth and Chepstow as he pushed into the Welsh Marches. The Normans used castles to subdue the Welsh, to plant settlements, and to press claims of lordship. Grosmont was one of three earth-and-timber strongholds in the Monnow valley, possibly commissioned by the earl himself, to protect the road from Wales to Hereford.

The first castle had a keep and a motte, a palisade, and a ditch. A borough was laid out beside it and became the village.

William FitzOsbern, 1st Earl of Hereford, was lord of Breteuil and one of the few proven companions of William the Conqueror at Hastings. Born about 1011, he was the son of Osbern the Steward, a nephew of Duchess Gunnor, and he inherited the honours of Pacy and Breteuil through his mother Emma. He was probably raised at the ducal court, became a steward like his father, and married Adeliza de Tosny about 1030. Together they founded Lyre Abbey and later Cormeilles Abbey, and he also founded Saint-Evroul.

He was an early and vigorous advocate of the invasion of England. Tradition holds that at the Council of Lillebonne he persuaded doubting Norman barons that the crossing was feasible. His younger brother, Osbern FitzOsbern, was a chaplain of Edward the Confessor and held the church of Bosham in Sussex, where Harold is shown at the opening of the Bayeux Tapestry, and was in a position to pass news from England. That brother later became bishop of Exeter.

After the conquest FitzOsbern was made an earl, with major lands in Gloucestershire, Herefordshire, Oxfordshire, and the Isle of Wight, and smaller authority in Berkshire, Dorset, Wiltshire, and Worcestershire. His chief residence was Carisbrooke Castle, one of many he built. In the summer of 1067, when the king returned to Normandy, FitzOsbern and Bishop Odo of Bayeux were left in charge of England. He accompanied the king in the subjugation of the south-west in 1068, attended the Whitsun court that May, and then fell ill for some months in Normandy.

In February or March 1069 he was sent to oversee the peace at York, where Gilbert de Ghent was castellan of the new castle, and he was back for the Easter court in April before returning north. Eadric the Wild campaigned in the West Midlands with Welsh princes who had lately been allies of the Anglo-Saxon kings. The revolt was crushed in 1069, and FitzOsbern is likely to have played a major part, though the details are uncertain. During that push westwards he and his followers began the Norman conquest of the Welsh kingdom of Gwent.

He was one of the great castle-builders of the conquest. Early castles attributed to him include Carisbrooke, Chepstow, Snodhill, Wigmore, Clifford, Berkeley, and Monmouth, and he created or improved the fortifications of Hereford and Shrewsbury. Grosmont belongs to that same generation of Marcher works, even though a later account places the first written record much later. In 1070 trouble arose in Flanders, where King William's brother-in-law Count Baldwin VI had died.

FitzOsbern died on 22 February 1071. The earl's lands in the region were slowly broken up after his son, Roger de Breteuil, rebelled against the Crown in 1075.

By the early twelfth century Grosmont was held by the Anglo-Norman nobleman Pain fitzJohn, also called Payn Fitz John. Accounts of the next decades do not agree, and both sequences have to be kept. One account says that a major Welsh revolt in 1135 led Stephen of England to bring Grosmont, Skenfrith, and White Castle back under the Crown as the single lordship of the Three Castles. Another says that it is not known exactly when the first castle was built, that the earliest record dates from 1142, and that the origins probably lie in the early years of the Norman conquest, the motte perhaps raised by William Fitz Osbern around 1070.

In that account Payn Fitz John gave the castle to Stephen in 1137 in exchange for the province of Archenfield. It stayed in royal hands for only two years before Brian Fitz Count of Abergavenny took it in 1139. In the middle of the twelfth century a charter granted it to Walter of Hereford, who united it with Skenfrith and White Castle. After Walter's death in 1160 it returned to royal control under Henry II and remained a royal fortress until 1201.

A further account says the first castle was in existence by 1154, or was built around 1154, as wooden buildings behind a palisade and a ditch, of which only the moat survives. Another places the foundation in 1137, a timber castle rebuilt in stone between about 1210 and 1330, with a bailey to the east.

Stephen of England, often called Stephen of Blois, was king from 22 December 1135 until his death on 25 October 1154. He was born in 1092 or 1096, the fourth son of Stephen-Henry, count of Blois, and of Adela, a daughter of William the Conqueror. His father died on crusade while Stephen was still young. Brought up by his mother and then placed in the court of his uncle Henry I, he received wide lands and married Matilda of Boulogne, whose inheritance in Kent and Boulogne made the couple among the richest in England.

He narrowly escaped the wreck of the White Ship in 1120, in which Henry I's son William Adelin drowned, and the succession was left open. When Henry died in 1135, Stephen crossed the Channel and took the throne with the help of his brother Henry, bishop of Winchester, arguing that order mattered more than his earlier oath to the Empress Matilda. His reign was the Anarchy, a civil war with Matilda, whose son Henry II succeeded him as the first Angevin king of England.

The early years of that reign were largely successful, but they were marked by attacks from David I of Scotland, from Welsh rebels, and from Matilda's husband Geoffrey Plantagenet, count of Anjou. In 1138 Matilda's half-brother Robert of Gloucester rebelled. Stephen and his adviser Waleran de Beaumont arrested a powerful family of bishops. When the Empress and Robert invaded in 1139, the revolt took hold in the south-west.

Stephen was captured at the battle of Lincoln in 1141, lost Normandy, and was freed only after his wife and William of Ypres captured Robert at the Rout of Winchester. The war then dragged on. Stephen tried to have his son Eustace crowned. Pope Eugene III refused.

In 1153 Matilda's son Henry invaded, the armies met at Wallingford, and neither side's barons wanted another pitched battle. Eustace died suddenly. By the Treaty of Winchester, Stephen recognised Henry as his heir and passed over his second son, William. He died the following year.

The restructuring of Grosmont belongs in that unsettled reign, whether it is told as a royal gathering of the Three Castles after the revolt of 1135 or as a short royal tenure from 1137, a seizure in 1139, and a mid-century charter to Walter of Hereford.

Conflict with the Welsh continued after the Anarchy. Following a period of détente under Henry II in the 1160s, the de Braose and de Mortimer families of the March attacked their Welsh rivals in the 1170s. That fighting led to a Welsh assault on nearby Abergavenny Castle in 1182. One William de Braose, the fourth lord of Bramber, who lived from about 1140 or 1150 until 1211, is remembered for the killing of Welsh princes at Abergavenny on Christmas Day in 1175.

The assault of 1182 is a separate event in the castle's story. In response, the Crown readied Grosmont for a possible Welsh attack. Over the next three years, fifteen pounds were spent under Ralph of Grosmont, a royal official, probably on the timber defences. Comparing medieval sums with later money is notoriously difficult.

For scale, the average annual income of a baron in the period was about two hundred pounds, so the works were a modest royal outlay on an existing timber castle rather than a new stone fortress.

In 1201 John of England gave the Three Castles to Hubert de Burgh. Hubert was a minor landowner who had become chamberlain of John's household while John was still a prince, and he grew more powerful once John was king. He began to upgrade the castles, starting at Grosmont, where he rebuilt the hall block in stone. The monument account leaves the date of that hall open.

Some evidence is taken to suggest that the block was an early feature, a rectangular stone keep of the late eleventh or early twelfth century, later remodelled by Hubert. Alternatively it was built by him between 1219 and 1232, when he put up the stone fortress still visible. A third dating makes the great hall the earliest masonry, of about 1210. The second build, in the first half of the thirteenth century, enclosed the inner ward with a stone curtain, three semi-circular towers, and a projecting gatehouse.

The last stage, probably around 1330, added a range of rooms outside the north curtain and enlarged and heightened the south-west tower.

John of England was king from 1199 until his death on 19 October 1216. He was born around Christmastide in 1166 or 1167, the youngest son of Henry II and Eleanor of Aquitaine, and he was nicknamed Lackland because a younger son was not expected to inherit much. He became his father's favourite after a failed revolt by his elder brothers, Henry the Young King, Richard, and Geoffrey. Henry II made him Lord of Ireland in 1177.

During the reign of his brother Richard I he tried and failed to rebel while Richard was on the Third Crusade, and he was proclaimed king after Richard died in 1199. Philip II of France recognised John's continental lands at the peace of Le Goulet in 1200. War resumed in 1202. Early victories gave way, through lack of resources and John's treatment of Norman, Breton, and Angevin nobles, to the collapse of the Angevin empire in northern France in 1204.

John spent the next decade trying to recover those lands, raising heavy revenue, reforming his forces, and rebuilding alliances. His dispute with Pope Innocent III over Stephen Langton as archbishop of Canterbury brought an interdict on church services in England from 1208 to 1214 and John's excommunication from 1209 to 1213. His attempt to defeat Philip failed when the French beat John's allies at Bouvines in 1214. Many barons then rebelled against his taxes and his treatment of great nobles.

Magna Carta was sealed in 1215 as a peace, and neither side kept it. Civil war followed, the barons aided by Philip's son Louis. John died of dysentery in eastern England in late 1216. Supporters of his young son Henry III defeated Louis and the rebel barons in the following year.

Hubert de Burgh, later earl of Kent, was born about 1170, of unknown parents at Burgh-next-Aylsham in Norfolk, and died before 5 May 1243. A case has been made that his father was Walter de Burgh and his mother Alice. The family were minor landholders in Norfolk and Suffolk, and Hubert inherited at least four manors. His elder brother was William de Burgh, who died in 1206 and founded the de Burgh line in Ireland.

Younger brothers were Geoffrey, archdeacon of Norwich and later bishop of Ely, and Thomas, castellan of Norwich. Hubert had entered Prince John's service by 1198. He served as chamberlain, as ambassador to Portugal, as sheriff of Dorset and Somerset, then of Berkshire and of Cornwall, and as custodian of Dover, Launceston, Windsor, and the Welsh Marches. Those offices brought him manors, baronies, and castles.

In 1202 John sent him to help defend Poitou against Philip II. He was castellan of Chinon in Touraine and guard of the captured Arthur, duke of Brittany. After most of Poitou fell, he held Chinon for a year until the castle was stormed in 1205 and he was taken. He remained a captive until 1207, and in that time his offices and grants passed to other men.

The castle account says he was captured fighting the French in 1205 and that, while he was imprisoned, John took the Three Castles back and gave them to William de Braose, one of Hubert's rivals. John then fell out with William and dispossessed him in 1207. William's son, also called William, used the chaos of the First Barons' War to retake the castles. Another William de Braose, who died in 1230, the son of Reginald de Braose, was later hanged by Llywelyn the Great.

The two Williams of the castle's ownership are the rival whom John endowed and then ruined, and the son who seized the castles in the civil war.

Once free, Hubert regained power. He was chief justiciar of England from 1215 to 1232 and justiciar of Ireland in 1232, and he was regent from 1219 to 1227 during Henry III's minority. He remained loyal to John in the baronial rebellion. John sent him to London with the bishop of Coventry in an unsuccessful attempt to make the city resist the barons.

With Philip d'Aubigny he gathered the king's troops at Rochester, and John then made peace. In Magna Carta he is listed among those who advised the king to seal it. His brother Geoffrey, bishop of Ely, was a witness, and Hubert was named to act for the king if the king were abroad. Soon afterwards he was declared chief justiciar of England and Ireland.

During the war of 1215 to 1217 he was sheriff of Kent and of Surrey and castellan of Canterbury and Dover. He held Dover through a siege that lasted until John died in October 1216 and the boy Henry III was crowned, and he denied Louis VIII the castle later in 1216. On 24 August 1217 a French fleet arrived off Sandwich to support Louis.

Hubert finally recovered the Three Castles in 1219, in Henry III's reign. He resumed work at Grosmont, rebuilding the timber walls in stone and adding three mural towers and a gatehouse. The result was secure, high-status accommodation. The hall block is a pilaster-buttressed building of two storeys, 96 by 32 feet, or 29.3 by 9.8 metres.

A spiral stair in the south-eastern corner linked the floors. The first floor held the hall and a solar, divided by a wooden partition. The hall had a fireplace in the middle of its outer wall, with two large windows on either side. The ground floor is described both as two service rooms lit by narrow loops and as a storeroom.

One account gives four narrow lancet windows on the ground floor and three large round-headed windows on the first floor. An external wooden stair led from the inner ward straight into the hall. The block would have closely resembled Hubert's hall at Christchurch Castle in Dorset. The mound under the castle is D-shaped, curved on the south-west and straight on the north-east.

It is unclear whether that was the original motte or a platform altered to take the rectangular hall. The stone castle stands on a roughly rectangular platform in a ditch about 6 metres deep, and the moat is about 20 metres across.

Hubert fell from power in 1232 and was stripped of the castles, which were put under Walerund Teutonicus, a royal servant. Henry III led an army into Wales in 1233 against Richard Marshal, 3rd Earl of Pembroke, and Marshal's Welsh allies, and camped outside Grosmont that November. Richard carried out a night attack on the encampment. He did not take the castle, but the rest of the king's army fled in confusion.

Richard Marshal, 3rd Earl of Pembroke, was born about 1191 and died on 15 April 1234. He was the son of William Marshal and Countess Isabel, and a younger brother of William Marshal the younger, who was born in 1190. His father's biography calls him the second-born son. Like his brothers he was educated in the liberal arts.

During his father's troubles with John in 1207 or 1208, Richard was demanded as a hostage, later released, and demanded again in 1212. John himself knighted him. He remained in the royal household and went with John to Poitou in 1214, where he fell seriously ill. After the Barons' War he appears to have crossed to France.

When news of his father's death reached Philip II's court in 1219, Richard was in the French king's household, placed there because he was to inherit his mother's Norman lands under his father's last testament.

After his mother died in March 1220 he received those lands, centred on Longueville and Orbec, and also the English lordship of Long Crendon in Buckinghamshire. His parents had not resolved the divided allegiance between the kings of England and France. In June 1220 Richard and his elder brother met Philip at Melun, and the king accepted the arrangement and took Richard's homage. About 1222 Richard married the twice-widowed Gervasia de Dinan, heir to her father's Breton lordship, and through her he secured claims to Ringwood in Hampshire and Burton Latimer in Northamptonshire.

In 1230, on campaign in Brittany, Earl William extracted a promise from his friend Henry III that if he died the king would not resist Richard's succession to the English Marshal lands, even though Richard was a sworn man of Louis of France. William returned ill and died childless on 6 April 1231. Henry kept his word. Richard arrived in England on 25 July 1231 and was welcomed at court.

His brother's death also cleared the way for Peter des Roches, bishop of Winchester and John's exiled favourite, to return and plot the fall of Hubert de Burgh. One of the bishop's first victims, once he seized power in 1233, was Gilbert Basset, a follower of the late earl. Peter de Maulay demanded a manor that had passed to Basset. The king backed des Roches.

When Basset resisted, the king abused him as a traitor. After a failed protest Basset fled to the southern March, and Richard sheltered his brother's ally and took up the cause. Richard was too suspicious to meet the king at Gloucester in mid-August 1233. The bishop of St Davids, a cousin of the earl, was sent to add to the pressure.

Richard may have hesitated before open rebellion, but once committed he sought to win. He allied with Prince Llywelyn ab Iorwerth of Gwynedd, long an enemy of his family. With Welsh support, in mid-October 1233 his army swept across South Wales and took the castles of Usk, Abergavenny, Newport, and Cardiff in quick succession.

Not everything went well. The chronicler Roger of Wendover says that Marshal and his knights came to Monmouth to look over the town before besieging it, and that they were seen from the walls by Baldwin III, count of Guînes, a Flemish noble whom Henry had entrusted with the defence, together with a mixed force of Flemings and Poitevins. The local lord, John of Monmouth, was absent. Baldwin thought Marshal had only a few men, rode out, and was turned on.

Marshal's army drove Baldwin's men back, but the castle held. Richard's ally Richard Siward, with what must have been the earl's consent, made a spectacular cavalry raid across England that at one point threatened London. Despite these successes Richard failed to win wider support among the earls and barons, and apart from mounted raids out of the March he lacked the means to carry the war to the king and his advisers. The November night attack outside Grosmont sits in that same season: a blow against the royal camp, not the capture of the castle itself.

The stalemate in England seems to have persuaded Richard to sail for Ireland on 2 February 1234. He found Leinster loyal. His younger brother Gilbert had, since the summer of 1233, made a truce with the justiciar Maurice fitz Gerald and with the rival lords Walter de Lacy and Richard de Burgh. That truce frustrated the earl.

Around the middle of March he attacked de Burgh, who had come out more strongly for the king, and with the Irish of Thomond he took several de Burgh castles. De Burgh and de Lacy struck back from Meath and besieged the Marshal castle of Kildare. On 1 April 1234 Richard and a small column of cavalry reached the siege lines on the Curragh. Templar brothers tried to negotiate.

In the mêlée the earl was cut off, unhorsed, and fatally wounded. He lingered for two weeks and died of his injuries on 15 April 1234. He was buried in the Franciscan friary at Kilkenny. His brother Gilbert, then a clergyman, succeeded him and had to salvage the Marshal inheritance and pursue the feud with the killers.

Richard's death ended the family's long link with its continental lands, because Gilbert did not inherit them. Gervasia, childless by Richard, died in 1238 or 1239.

Hubert was reconciled with the king in 1234 and the castles were returned, only for him to fall out with Henry III again in 1239. Grosmont was taken back and put once more under Walerund, who finished some of Hubert's work, including a new chapel. In 1254 the castle and its sister fortifications were granted to Henry's eldest son, the future king, Edward. The Welsh threat had not ended.

In 1262 the castle was readied after Prince Llywelyn ap Gruffudd attacked Abergavenny. Its constable, Gilbert Talbot, was ordered to garrison it by every man, and at whatever cost. The threat passed without an attack on Grosmont.

Llywelyn ap Gruffudd, called Llywelyn the Last, was prince of Gwynedd from 1255 until his death, and he died in an ambush at Cilmeri on 11 December 1282. After campaigns across Wales in 1257 he proclaimed himself prince of Wales in 1258, and Henry III recognised him as such in 1267 by the Treaty of Montgomery. His death was one of the final events in the conquest of Wales by Edward I of England. That conquest ran from 1277 to 1283, in two campaigns.

In 1277 Edward greatly reduced Llywelyn's territory. In 1282 and 1283 he overran it, and the other remaining Welsh principalities with it. By the thirteenth century Wales was divided between native principalities and the lands of the Anglo-Norman Marcher lords. Gwynedd was the leading principality.

Its princes had made the other Welsh princes their vassals and had taken the title prince of Wales. Earlier kings had tried to seize the native territories. Edward's war against Llywelyn, the last independent prince, achieved that control on a lasting basis.

Most of the conquered land was kept as a royal fief and later, by custom, became the endowment of the heir to the English throne, with the title prince of Wales. The rest was granted to Edward's supporters as new Marcher lordships. Welsh supporters of the English king were also rewarded, under feudal tenure. Royal land was organised under the Statute of Rhuddlan, divided into six shires, and incorporated into the new Principality of Wales.

The country was not effectively folded into the kingdom of England until the Laws in Wales of 1535 to 1542, but Edward's conquest marked the end of Welsh independence. The background was a long fluctuation. After 1066 the Normans seized much of Wales and set up quasi-independent Marcher lordships. Welsh principalities such as Gwynedd, Powys, and Deheubarth survived, and from the end of the eleventh century the Welsh pushed the Normans back.

Henry II several times sought conquest or suzerainty. By the end of the twelfth century the Marcher lordships were reduced to the south and south-east. Gwynedd dominated the first half of the thirteenth century. Wars with England in 1241 and 1245, and a succession dispute, weakened it and let Henry III seize Perfeddwlad, the Four Cantrefs.

From 1256 Llywelyn took that land back. The Treaty of Montgomery restored peace, recognised his title, and accepted his reconquest, in return for homage. Sporadic war with Marcher lords, among them Gilbert de Clare, Roger Mortimer, and Humphrey de Bohun, continued. Henry III died in 1272.

Edward, a vigorous commander where his father had been ineffective, faced growing tension in 1274 when Gruffydd ap Gwenwynwyn of Powys and Llywelyn's younger brother Dafydd ap Gruffydd defected and sought his protection.

Edward I was born on the night of 17 to 18 June 1239 at the Palace of Westminster, the eldest son of Henry III and Eleanor of Provence, and he died on 7 July 1307. He was king of England from 1272 to 1307, lord of Ireland, and from 1254 to 1306 duke of Aquitaine as a vassal of the French king. Before his accession he was called the Lord Edward. He was also known as Edward Longshanks and as the Hammer of the Scots.

In 1259 he briefly sided with the baronial reformers and the Provisions of Oxford, then reconciled with his father and stayed loyal through the Second Barons' War. After the battle of Lewes the rebellious barons held him hostage. He escaped after a few months and defeated Simon de Montfort at Evesham in 1265. Within two years the rebellion was extinguished.

In 1270 he left on the Ninth Crusade. He was on the way home in 1272 when he learned of his father's death, reached England in 1274, and was crowned at Westminster Abbey.

He spent much of the reign on administration and common law, inquired into feudal liberties, and issued statutes on criminal and property law, but his attention turned increasingly to war. After a smaller conflict in Wales in 1276 and 1277, he answered the war of 1282 and 1283 by conquering the country, building castles and towns, and settling them with English people. When the heir to the Scottish throne died, he was invited to arbitrate the succession, claimed feudal suzerainty, and invaded. The First Scottish War of Independence outlasted him.

He was also at war with France, a Scottish ally, after Philip IV confiscated Gascony. The duchy was recovered, but the French war eased the pressure on Scotland. By the mid-1290s the cost of these campaigns brought heavy taxation and opposition from laymen and clergy. In Ireland he drew out soldiers, supplies, and money, and left decay, lawlessness, and a revival of his enemies in Gaelic territories.

He died in 1307 and left his son Edward II a Scottish war and a burden of debt and politics. He was a tall man, six feet and two inches, and a frightening one. Some later historians have praised his law and his restoration of royal authority after Henry III, and the settling of Parliament as a permanent institution. Others have condemned his uncompromising treatment of his nobles, his dealings with Wales, Scotland, and Ireland, and the Edict of Expulsion of 1290, which expelled the Jews from England.

For Grosmont, the consequence of his Welsh wars was direct. The Conquest of Wales by Edward I of England in 1282 removed much of the castle's military usefulness.

Edmund Crouchback received the Three Castles in 1267. He was capitaneus, the captain, of the royal forces in Wales, and for many centuries the castles were held by the earldom and later the duchy of Lancaster, until they were sold in 1825. Another account says that the earl of Lancaster was granted the Three Castles by his brother, Edward I, after the subjugation of Wales, and that in the fourteenth century the castle ceased to have a military function and was converted into accommodation for that earl. The two statements do not name the same moment.

The grant of 1267 comes before the campaigns of 1277 and 1282. The later comforts of the house belong to the fourteenth century.

Edmund Crouchback was born in London on 16 January 1245 and died on 5 June 1296. He was the second surviving son of Henry III and Eleanor of Provence, and the younger brother of Edward I, to whom he was loyal as a diplomat and a soldier. Henry named him for the ninth-century East Anglian king and saint, to whom he had prayed for a second son. Edmund was baptised by 3 February 1245 and spent much of his childhood at Windsor with his brothers and sisters Edward, Margaret, Beatrice, and Catherine.

He was earl of Leicester from 1265 to 1296, earl of Lancaster from 1267 to 1296, and earl of Derby from 1269 to 1296, and he was count palatine of Champagne from 1276 to 1284. In 1254, at the age of nine, he was drawn into the Sicilian business, in which Henry accepted a papal offer of the kingdom of Sicily. Edmund prepared to be king. Henry could not fund the venture.

The papacy withdrew the grant and gave it to Edmund's uncle, Charles I of Anjou. The business outraged the barons led by Simon de Montfort, earl of Leicester and Edmund's uncle, and it was cited among the reasons for limiting Henry's power. The quarrel became the Second Barons' War. Edmund supported the royal government.

It triumphed after Montfort's death at Evesham in 1265.

Edmund received the lands and titles of Montfort and of the defeated barons Nicholas Segrave and Robert de Ferrers, sixth earl of Derby, and became earl of Lancaster, Leicester, and Derby. Known above all as earl of Lancaster, he became the most powerful baron in England. He went with Edward on crusade to the Holy Land. The epithet Crouchback is explained as a corruption of cross-back, from the cross stitched on his clothes.

After the death of his first wife, Aveline de Forz, his aunt Margaret of Provence, dowager queen of France, arranged his marriage to Blanche of Artois, the widowed queen of Navarre and countess of Champagne. With Blanche he governed Champagne as count palatine in the name of his stepdaughter Joan until Joan came of age. He helped Edward in the conquest of Wales, pressed his aunt Margaret's claims in Provence against Charles of Anjou, and managed Ponthieu for his sister-in-law Eleanor of Castile.

When Philip IV of France, Edmund's stepson-in-law, demanded in 1293 that Edward come to Paris to answer for damage done by English mariners, Edward sent Edmund to mediate. Edmund negotiated that France would occupy Gascony for forty days and that Edward would marry Philip's half-sister Margaret. When the forty days ended, Philip refused to give Gascony back and called Edward to answer again. Edmund and Edward renounced their homage and prepared for war.

Edmund sailed for Gascony, besieged Bordeaux, could not pay his troops, was deserted by his army, and retreated to Bayonne, where he died of illness in 1296. His body was brought back to England and buried in Westminster Abbey in 1301. While he held Grosmont, the borough beside the castle was already old. A borough charter was granted possibly in 1219, and by 1250 there may have been as many as 160 burgage plots.

The church of St Nicholas, whose tower and other parts were built by Edmund for his mother Eleanor of Provence, stands in that planted town. The wider community later included Llangattock Lingoed, Llangua, and Llanvetherine.

Under either Henry of Lancaster or his son Henry of Grosmont, the interior was modernised in the first half of the fourteenth century into a suite of high-quality apartments. A deer park was kept around the castle. At that time the castle formed a small but very comfortable residence. Henry of Grosmont, later the first duke of Lancaster, is recorded as having been born at the castle.

The austere military building was softened. Larger windows replaced arrow slits. Fireplaces and garderobes were added in the towers. Two structures were built outside the curtain on the north, over the remains of one of the round towers and the old postern.

The north block is three distinct buildings, the largest a residential tower of three storeys. Its chimney is octagonal, with a carved top, and the chimney of the western of the two outer structures is an elaborate ashlar pot, an exceptional medieval survival. The south-west tower was made into a three-storey suite and its basement was filled in. The west tower, also of three storeys, was altered in the same century and its basement filled in.

The gatehouse, originally a rectangular tower of two storeys, received fourteenth-century additions, including a buttressed drawbridge pit, of which only limited parts survive. The pit can still be seen below the gatehouse on the south-east.

The castle originally had an inner and an outer ward. The outer ward has been encroached on by gardens. It would have held a rectangular storehouse or stable. The inner ward is the stone castle: gatehouse, mural towers, hall, and north block, all inside the ditch.

Timber buildings once stood against the outer face of the stone wall as lodgings for servants, and only limited traces of them remain. A probable bailey can be traced on the south-east and north-east as a scarped slope about 4 metres high, and on the north as two banks about 0.3 metres high and 9 metres wide, with a ditch about 1 metre deep between them. The design of the stone curtain, three circular towers, and gatehouse has been compared with Cilgerran. The mound was long thought to be artificial, thrown up by digging the surrounding ditch.

On clearance, the raised centre appeared instead to be tumble from the walls.

The castle's last military role came in the revolt of Owain Glyndŵr at the start of the fifteenth century. Owain ap Gruffudd Fychan, or Owain Glyndŵr, was born about 1359 and died in hiding about 1416. He was a Welsh nobleman and commander who led a revolt to establish an independent Wales. His supporters acclaimed him prince of Wales on 16 September 1400.

In 1400 he was lord of Glyndyfrdwy, and a dispute with his English neighbour Reginald de Grey was a symptom of a wider hostility that became a national rising of Welsh countrymen and nobles against English forces. Penal laws against the Welsh deepened the unrest and increased his support. After successful sieges and battlefield victories, the rebellion controlled most of the country between 1404 and 1405. In 1404 he held a parliament at Machynlleth, with envoys from France, Scotland, and the Spanish kingdoms of Castile and León, and with representatives from every region of Wales.

Military aid came from France, Brittany, and Scotland. In the Pennal letter of 1406 he wrote of plans for two universities, one in the north and one in the south, and for restoring the laws of Hywel Dda. He also aimed at an independent Welsh church and an alliance with Charles VI of France. A French army landed in Wales in 1405.

Stronger English pressure and the lack of lasting foreign help cost him all rebel territory by 1409. He was never captured. He disappeared from the record in 1412 and is thought to have died in hiding about four years later. The rising is the last major manifestation of Welsh independence before the annexation of Wales into England in 1542 and 1543.

The dates and the shape of the fighting at Grosmont are not the same from one account to the next, and each version has to stand. One account places a battle between the Welsh and Richard Beauchamp, thirteenth earl of Warwick, near Grosmont in 1404, and an English victory. It says the castle was besieged the next year by Owain's son Gruffudd, and that an English force sent by Prince Henry relieved it. Another says the castle was attacked and besieged by Gruffudd in 1405 and relieved by a force from Hereford.

A third says that early in 1406 Owain's forces suffered defeats at Grosmont and at Usk. By 1407 the English had retaken Anglesey and much of south Wales. They took Aberystwyth Castle in 1408 and Harlech Castle in February 1409, which ended Owain's territorial rule. He ignored two offers of pardon from the new king, Henry V, and small pockets of resistance continued by guerrilla fighting.

The prince who sent help was Henry of Monmouth, later Henry V of England. He was born on 16 September 1386 and died on 31 August 1422. He was the eldest son of Henry IV, and he became heir apparent and prince of Wales after his father took the throne from Richard II in 1399. During his father's reign he gained his military experience in Wales against this rebellion and against the Percy family of Northumberland, and he played an important part at the battle of Shrewsbury when he was only sixteen.

As Henry IV's health failed, the prince took a larger place in government, though the two men quarrelled. He became king in March 1413, renewed the war with France in 1415, besieged Harfleur, and won at Agincourt. A second expedition from 1417 conquered Normandy. By the Treaty of Troyes in 1420 he was recognised as heir and regent of France.

He died in 1422. At Grosmont he was still the prince, not yet the king, and the letter he wrote home is the sole evidence cited for the fight of March 1405.

That letter, from Prince Henry to his father Henry IV, is dated 11 March 1405. It says that on Wednesday the eleventh day of that March, the king's rebels from Glamorgan, Morgannwg, Usk, Netherwent, and Overwent assembled to the number of eight thousand men by their own account. On that Wednesday morning they burned part of the town of Grosmont, within the king's lordship of Monmouth. The prince at once sent out his cousin, the Lord Talbot, and a small company of his household.

With them assembled the knights William Newport and John Greyndour. They were only a very small force. The letter says that victory is not in the number of men, and that by the power of God and the aid of the Trinity the king's men won the field, vanquished the rebels, and killed, by a reliable account on the field at the return from the pursuit, some say eight hundred and some say a thousand. The letter is about the burning of part of the town and a field victory.

It does not, in that text, describe the storming of the castle.

A further account of the same rising says that Glyndŵr's ally and captain Rhys Gethin raised a force of maybe eight thousand, marched on Grosmont, and burned the town to the ground. It describes Grosmont then as a large settlement, with only Abergavenny and Carmarthen larger in the whole of south Wales. It says Prince Henry sent men led by John Talbot, later the first earl of Shrewsbury, with Sir William Newport and Sir John Greynder, from Hereford, and that they killed eight hundred to a thousand and captured Owain's secretary, Owen ap Gruffydd ap Rhisiant, and Owain's brother-in-law John Hanmer. Both captives survived and were imprisoned in the Tower of London.

The names sit close to the letter's Lord Talbot, William Newport, and John Greyndour, but the letter's eight thousand is by the rebels' own account, the letter's dead are given as two rival figures, and the letter says part of the town was burned rather than the whole town. The exact site of the battlefield remains undetermined. Modern mapping marks it in direct association with the castle, but the evidence for that identification is unclear, and it was not marked on earlier editions of those maps. Documentary research and fieldwork, including a metal-detector survey between 2012 and 2014, were undertaken so that the fight could be considered for an inventory of historic battlefields.

A report of that survey was produced in March 2012. They did not fix the spot.

By 1538 the castle had fallen out of use and then into ruin. A survey of 1563 notes that the bridge had collapsed and that, although the outer walls were intact, the interior was decayed and the building materials inside had been removed or were rotten. A description of 1613 called it ruinous and decayed. The estates of the Three Castles were sold in 1825 to Henry Somerset, sixth duke of Beaufort.

The same family later replaced a timber town hall: the duke of Beaufort built the present town hall in 1832, and a descendant offered it to the parish council in May 1902. The borough kept its corporation until 1857, when it still had a mayor and an official ale taster. In 1902 Henry Somerset, the ninth duke, sold the castle itself to Sir Joseph Bradney, a soldier and local historian. Evidence given in 1909 to a royal commission on the ancient monuments of Wales and Monmouthshire stated that Grosmont was exceptionally well looked after.

The castle was placed in the care of the state in 1922 by Frances Lucas-Scudamore. Another account dates that transfer to 1923. Conservation included clearing debris from the basement of the north block. Clearance of the moats and wards, carried out with the consolidation of the masonry, produced finds that were thought worth listing, at Grosmont and at other castles treated in the same campaign.

Clearances in the 1920s and 1930s, and excavations in the 1950s, uncovered artefacts from White Castle, Skenfrith, and Grosmont, among them large quantities of medieval pottery. Later study of that pottery has distinguished vessel types and wares from particular regions, and so the trade and consumption of the three castles. During the clearance and restoration of 1932, sherds were found at Grosmont from a vessel like a narrow-necked jar, underglaze-painted in black and turquoise. They are Raqqa ware, quartz-tempered.

They are described as fragments of a fourteenth-century jar from Raqqa in Syria, a foreign import, possibly a souvenir from the Crusades. The recorded weight of those sherds is 21.3 grams. A geophysical survey of the castle was made in 1990. No published result of that survey is set out beside the note that it took place, so the note of the survey cannot be turned into a list of discoveries.

In the twenty-first century the ruin is protected as a listed building of the highest grade and as a scheduled monument. The scheduled remains are the medieval castle, and the ground around them is judged likely to hold further structural evidence and intact deposits. The monument is described as well preserved and as an important relic of the medieval landscape, with the potential to add to what is known of medieval defensive practice. The footbridge across the historic ditch was refurbished from February 2026, with a completion aimed at September 2026.

Deteriorated timbers in the bridge and its supports were to be repaired or replaced while the original design was kept, and the masonry of the abutments was to be repaired. The castle has since been opened to visitors while the final work on the bridge is finished.

Entry is free. The site is open from 10am to 4pm from 1 April through to 31 March, with last admission thirty minutes before closing, and it is closed on 24, 25, and 26 December and on 1 January. Dogs on short leads are allowed onto the ground-floor levels. Smoking is not allowed.

Visitors are not to climb the walls or to cross the guardrails, because of hidden drops and the risk of falling masonry. Those rules belong to the site itself. What a visitor meets is the ditch, the broken gatehouse, the hall, the towers with their filled basements, and the north block with its carved chimney, the comfortable rooms of the fourteenth century built over a castle that had been raised, in earth and then in stone, to hold a road from Wales to Hereford.