The Trilateral of Skenfrith, Grosmont and White Castle

Skenfrith Castle, Gwent.

Skenfrith Castle is the only low-lying fortress of the three castles of Skenfrith, Grosmont and White Castle, now known as the castles of the Trilateral. Like the other two castles Skenfrith is remarkably well-preserved, standing mostly to wallwalk height. Again we have no early reference as to the foundation of the fortress, though a castle certainly existed here by 1160 when it came into the king’s hands with Grosmont and White Castle. In 1187 the engineer Ralph Grosmont was instructed by King Henry II to rebuild the castle in stone. The eastern wall and possibly north-eastern tower of the castle, built in a totally different style to the rest of the fortress, was constructed by Ralph. However this work proved abortive and Henry II cancelled the building work in 1188 as unnecessary. In 1193, Sheriff William Braose pushed the unfinished castle into rapid service by placing a palisade around the other three sides of the ditch. A prison was later built within the stockade.

From this time on Skenfrith castle has largely the same history as Grosmont castle. In 1219 Hubert Burgh began to build the other three sides of the unfinished castle enceinte in stone. His work is characterized by the fine and high batter on the north, south and west sides of the castle. However before a year was out this castle was devastated by heavy flooding in the Monnow valley. Hubert therefore filled the interior of the first castle with river gravel and built a new castle on top of the first one! The hall of this first castle still remains, having been buried in gravel from 1220 until the 1950's excavations. This hall is remarkably well-preserved with the jambs of doors and windows in as good a condition as when they were first cut nearly 800 years ago. Even the original iron door hinges (below left) and window bars (below right) have survived from this era.




(Right: view the keep from the base of the first hall showing the fine tall 'Hubert Burgh' batter.)

In 1239 the castle was seized by King Henry III, who in 1244 placed a lead roof on top of the king’s tower or central keep. This round tower in the middle of the castle was the last part of the fortress constructed by Hubert Burgh, and is not, as is often stated, built on the old castle motte. The recent excavations conclusively proved that this tower was built on top of the thirteenth century gravel used to infill the first castle of 1219. Another dating feature of this tower can be found in the collapsed stairway built into a buttress in its western wall. This is not a standard spiral stair, but a series of semi-circular stairways. Although much damaged it can be seen to have been similar to the stairs that still exist in the gatehouse of White Castle. This work, with its unusual stairs, was also undertaken by Earl Hubert Burgh. It may have been King Henry’s eldest son, the Lord Edward, later King Edward I (1272-1307), who when he owned the castle between 1254 and 1267, built the solid half round tower in the castle’s vulnerable west wall, although once again there is no reason why this work was not carried out under the auspices of Hubert Burgh. The fortress was once surrounded by a twenty feet deep paved moat which fed a mill to the south. Today the castle stands mostly to wall walk height and is in much the same state as it was in 1538 when the antiquarian Leyland noted that Skenfrith castle ‘yet standith’.  Other round keeps in the vicinity stand at Pembridge, Tretower, Longtown and Bronllys.  The round keep at Monmouth has been demolished.


(Below: view of the earlier east wall of the castle with its normal batter and the central original ground level postern.)

Text extracted from a full history and architectural description of Skenfrith Castle and the families of Fitz Osbern, Ballon, Fitz Count,  Burgh, Braose and Plantagenet of Grosmont.  [Malvern, 2008].


Grosmont Castle, Gwent.

Grosmont castle is a remarkably well-preserved three phase fortress. It was quite possibly founded by Earl William Fitz Osbern during his invasion of South Wales in 1070. Earl William was killed the next year and his son Roger was stripped of his lands in 1075. The land on which Grosmont castle was built now passed either under the control of the Ballon family of Abergavenny or the Lacys of Weobley and Longtown. The powerful Marcher baron Pain Fitz John acquired Grosmont in the reign of King Henry I (1100-35) and converted it into the head of a lordship which stretched from White Castle in the west to Orcop castle in the east. During the early twelfth century the castle was the centre or caput of what was known as the honour of Grosmont. The great hall was one of the first features constructed of the castle and this was used as the civil capital of the lordship. Certainly this hall was not the work of Earl Hubert Burgh in the early thirteenth century as is often claimed. Just compare the one surviving door jamb of the hall to those of Hubert Burgh’s work which can also be seen within his fortresses at Skenfrith and White Castle. One is typically ‘twelfth’ century, the others ‘thirteenth’.

The early hall at Grosmont was most probably built within forty years either side of 1110. It still stands two stories high and has many features of comfort within its walls. There are many reasons to believe that this hall was built early in the castle’s history for the evidence points clearly to Grosmont castle having been fortified in stone from the first. Who actually first built the castle though, is more of a problem.  The hall-keep at Chepstow is much longer than that at Grosmont, but may date to a similar era.  The hall-keep at Monmouth castle is of more similar demensions and could also be early.

Both the first earls of Hereford and Pain Fitz John had a great deal of wealth and ruled Gwent at a time when the stable rule of the Normans in Wales seemed inevitable. Grosmont hall is certainly not a fortress. It was built as the administrative centre of a barony with both comfort and administration in mind. White Castle to the west, however, was built as a fortress from the first, probably in concert with the foundation of Grosmont. Orcop to the east, a true motte and bailey castle, may be older.

(Below right: Prince Edmund's new keep with its great two storey false entrance. The main entrance to the upper floors was from wall walk height.)

In 1134 rebellion broke out in Wales and in July 1137 Pain Fitz John was killed in action fighting against the Welsh. Immediately before his death Pain granted all his honour of Grosmont to King Stephen in exchange for the province of Archenfield. With the Angevin rebellion of 1139 Brian Fitz Count of Abergavenny took Grosmont castle from the king and in 1142 granted it by charter to Walter Hereford. This is our first certain historical mention of the fortress. Walter was killed around 1160 fighting in the Holy Land. At this point King Henry II (1154-89) reclaimed the castle and placed royal soldiers within its walls. The castle, requiring little maintenance, remained a royal fortress for the next forty years. In 1201 it was granted to Hubert Burgh ‘for his maintenance’ in the wars of the period. In 1205 he was wounded almost to death in the Loire valley and the castle passed for a few years to the Braose family while Hubert recovered his health. After the death of King John in 1216 Hubert regained his castles in the Welsh Marches in 1219. It was Hubert who was responsible for turning the administrative castle of Grosmont into a fortress. Royal records from when Hubert was running the government of England, show that he was undertaking building work at Grosmont between 1224 and 1226. His work gave the castle much of its appearance today. His buildings included the gatehouse, which has mostly disappeared in the last 100 years, and the three D shaped towers in the castle’s enceinte. In 1233 the castle witnessed the rout of King Henry III’s army by rebel English and Welsh forces, who included in their midst Earl Hubert Burgh himself! In the aftermath of this victory Hubert was granted back Grosmont castle and he held it until his final fall from grace in 1239.

In 1267 King Henry III granted the castle to his second son Prince Edmund and this man undertook the conversion of the fortress of Earl Hubert Burgh into one of his main residences. He demolished one of Hubert Burgh’s D shaped towers and built accommodation over it and raised the height and extended the south-west tower to make it into a 5 storeyed great tower or keep. The living quarters of this massive tower could only be approached via a wooden stairway to the north. To the east was a giant false doorway which only allowed access to the ground and first floors. The steps currently seen rising up to the castle wall walk from this doorway is the work of twentieth century restorers who are also responsible for the creation of much of the double doorway into the early hall. Most of Prince Edmund’s rebuilding at Grosmont was carried out probably in the period 1274 to 1294. Part of this reconstruction included the building of the great chimney of which Grosmont is justifiably famous.



(Below left: Photograph showing the one remaining jamb of the hall showing a pillar-type design of the twelfth century.  Below right photograph showing one of the decorated gatehouse jambs of the Hubert era, ie. thirteenth century.)

Before leaving the village of Grosmont be sure to visit the church, the nave of which is built in the same style as the early great hall of the castle. The tower and other parts of the church fabric were built by Edmund for his mother, Queen Eleanor, the wife of Henry III. Within its walls are the much eroded remains of an effigy of a thirteenth century knight. There is now no evidence to this knight’s identity, but perhaps he was the engineer Ralph Grosmont, so strongly entwined with the history of all three royal castles of Skenfrith, Grosmont and White Castle.


Text extracted from a full history and architectural description of Grosmont Castle and the families of Fitz Osbern, Ballon, Fitz Count, Burgh, Braose and Plantagent of Grosmont [ISBN 1899376569].

The new book consists of 203 A4 pages with 168 illustrations and photographs.

Available for £34.95

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White Castle or Llantilio Castle, Gwent

White Castle is undoubtedly the most visually impressive of the three castles of the Trilateral. It may also be the oldest and was certainly the main fortress of the twelfth century barony of Grosmont. It was built on a hill with magnificent views to north, south and west and as such was clearly a military outpost for the barony and a watch post against the Welsh. Quite possibly it was founded before 1075 when nearby Abergavenny castle was probably commenced in the lower ground to the west. White Castle is surrounded by formidable wet moats which alone could have laughed any siege to scorn, not that one was ever attempted! Clearly seen within the current remains are the foundations of an old square keep of the eleventh or twelfth century (foundations in top left of photo below). This tower was demolished early in the Middle Ages and may have been of a similar construction and type to that still existing at Goodrich castle. This early fortress may well have been the work of Earl William Fitz Osbern or his son, Roger, before 1075. The plan of this first castle has some similarities to Usk castle to the south which may also have been founded by them. After 1075 the castle’s history followed that of Grosmont, the caput of the barony.

The castle was stormed in late May 1182 after the defeat of William Braose and Sheriff Ranulf Poher at the battle of Dinesgtow.  The castle then remained under Welsh control until 1184 when it was returned by the authority of Rhys ap Gruffydd to the king.  King Henry II then ordered White Castle refortified. In 1185 the royal engineer Ralph Grosmont appears to have divided the first castle into two unequal parts, building the towering curtain wall which still survives around the inner, northern ward (photo above). There was probably also a gatehouse next to the original, now demolished, keep reached from the newly created hornwork, or southern section of the old bailey. The ditch between this hornwork and the inner castle is not as deep as that surrounding the whole defence and was obviously dug at a different time to the first moat. This work was finished in 1187 and the castle remained unaltered until 1229 when royal records show that Hubert Burgh began to alter the site.

It was Earl Hubert Burgh of Kent who built the new twin-towered gatehouse to the north and reversed the orientation of the castle. This bares simularities to Hubert's other gatehouses at Montgomery, Dover and Hadleigh.  The northern Marcher castles of Whittington and Beeston also have early gatehouses of this type.  Hubert also built new D shaped towers to the east and west of Ralph Grosmont’s curtain wall (photo right). This building session was interrupted in 1232 when Hubert was arrested and dispossessed of his estates. Reinstated in 1234 he continued to work on the castle building the chapel tower and a new D shaped ‘great tower’ to the south. He also demolished the old keep (photo above) and built a new outer ward to the north. That this work was undertaken by Hubert and not later lords is demonstrated by the similarities between his work at White Castle and the defences of Skenfrith and Grosmont, and perhaps most importantly of all, those features still to be seen in the contemporary Montgomery and Dover castles.

King Henry III seized White Castle in 1239 when it must have looked much as it does today. Some internal work was carried out in the early 1240's and in 1438 the outer face of the north-eastern gatetower had to be rebuilt (photo below). Notice how the old arrowslits in this tower were not replaced. The other fine offset arrowslits built by Hubert Burgh are one of the treasures of the castle as too are its deep and impressive moats, so beautiful when full of daffodils in the spring.











Further details about the dating of White Castle can be found here.

Text extracted from a full history and architectural description in 

Llantilio or White Castle and the families of Fitz Osbern, Ballon, Fitz Count, Burgh, Braose and Plantagenet of Grosmont

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Why not join me at other Lost Welsh Castles next Spring?  Please see the information on tours at Scholarly Sojourns.

Copyright©1994-2004 Paul Martin Remfry