Medieval Battles


The Battle of Bryn Glas (1402) was fought between the forces of Owain Glyndŵr and Sir Edmund Mortimer. The Welsh had raided deep into the latter's territory and the English followed in hot pursuit but were decisively defeated when Glyndŵr's men turned to fight. Mortimer was captured and later changed sides contributing to the destabilisation of Henry IV's regime.

Historical Background


By the close of the fourteenth century, Wales had been under English rule for over one hundred years and had seen the imposition of an administrative system which was brutal and prejudicial to the rights and interests of the native Welsh. Resentment simmered but was partly contained by the Prince of Wales which, since the conquest, had been a post held by the King's eldest son. This was seen by the native Welsh as a good check to the otherwise unlimited power of the Marcher Lords and which had started to engender Welsh loyalty to the Crown. In particular Richard II, who had been created Prince of Wales in 1376, had successfully recruited large numbers of loyal Welsh troops to serve him. In England however, Richard II's reign was viewed as a tyrannical failure which had seen oppression at home and significant reversals on the continent. He was deeply unpopular and successfully alienated many of his key magnates. The issue came to a head in 1399 when the King was overthrown by Henry Bolingbroke. Richard was captured at Flint Castle, forced to abdicate and was subsequently murdered whilst the newly enthroned Henry IV appointed his son, Henry of Monmouth (later Henry V), as Prince of Wales. Such regime change was not welcomed and led to wide scale indignation amongst the Welsh.


The spark that ignited this simmering discontentment was a land dispute between Lord Reginald Grey and Owain Glyndŵr. The latter was descended from the Princes of Gwynedd but was in his forties by 1400 and, as Lord of Glyndyfrdwy, had vested interests to protect. He was also a London trained lawyer and was married to an English wife. Despite all this, in 1400 Glyndŵr was pushed into rebellion when Grey seized control of a parcel of land at Croesau (now called Bryn Eglwys). Glyndŵr petitioned the English Government for redress but his plea was ignored. Moreover Grey sought to aggravate the situation by undermining Glyndŵr firstly by failing to deliver a Royal summons and then letting it be known that he intended to "burn and slay" the Welshman's territory. When Glyndŵr wrote back promising to reciprocate, Grey had him denounced as a traitor. Glyndŵr was outraged and on the 16 September 1400 proclaimed himself as Prince of Wales.


Welshmen flocked to Glyndŵr's cause and on the 18 September 1400 Ruthin town (but not the castle) was burnt. A trail of destruction followed as DenbighFlint, Hawarden, Holt, Rhuddlan, Oswestry and then Welshpool were sacked. Henry IV tried to bring Glyndŵr to battle but the Welshman evaded a pitched engagement and instead led a guerrilla war against the English including successfully ambushing the Royal army at Hyddgen in Summer 1401. Furthermore Glyndŵr opened negotiations with the French and Scots as well as English magnates disaffected by the new Lancastrian regime. In early 1402 Henry IV tried once more to crush the rebellion but the campaign ended in another Welsh victory at the Battle of Fyrnwy (1402) which saw the capture of Lord Grey, doubtless a moment of significant satisfaction for Glyndŵr.




In June 1402 Glyndŵr led his men on raid into Maelienydd, a Lordship owned by the powerful Mortimer family. Settlements were raided and churches burnt as the Welsh sought to discredit and destroy the power of the Marcher Lords. In response Sir Edmund Mortimer hastily mustered his forces at Ludlow and also recruited a significant number of Welsh archers. A Welsh raid on Knighton prompted him to deploy in pursuit and he hoped to catch the Welsh force before they disappeared once more. The English marched along the Lugg valley arriving in Whitton by 21 June 1402.




The English army was under the command of Edmund Mortimer, uncle of the Earl of March. It consisted of a force raised predominantly from Mortimer estates across Herefordshire and was joined by various local magnates including Kinard de la Bare, Thomas Clanvow, Waiter Devereux and Robert Whitney - all of whom had extensive experience of fighting in the Welsh Marches. Mortimer had also recruited significant numbers of Welsh archers.


The Welsh force was significantly smaller than the English army and it is likely that Owain Glyndŵr himself was not present. Instead the army was under the command of Rhys Gethin, an experienced soldier. The Welsh forces were poorly equipped by comparison to the leading elements of the English army certainly in terms of armour.

The Battle


The battle was fought on 22 June 1402 on a hill near modern Pilleth. Although dispute rages about the extent of the battlefield, the centre of the fighting is securely placed around St Mary's church as evidenced by discovery of significant numbers of grave pits.


- Stage 1: Deployment

On the morning of 22 June 1402 the English hastily advanced from Whitton hoping to catch-up with the Welsh. However, Gethin was well aware of their approach and had deployed the bulk of his forces on the high ground overlooking the Lugg valley. He left a small vanguard of archers on the valley floor to intercept and disrupt the English approach.


- Stage 2: Welsh Vanguard

The Welsh vanguard gave the attackers no opportunity to deploy in battle array and launched a furious arrow attack on the English. They then withdrew uphill, firing as they went, coaxing the English to follow who duly took the bait and commenced scaling the 1:4 gradient hill. However, the English were weighed down with their armour whilst the lighter Welsh kept ahead of them.


- Stage 3: Welsh Attack

As the English forces became disorganised and tired, the Welsh infantry attacked. From their position on the summit of Bryn Glas, they charged down the hill at full pelt. Mortimer ordered his archers to fire upon the charging Welsh in order to defuse their attack. However, at this point Mortimer's Welsh forces seem to have defected en mass to the opposing side. They not only refused to fire upon Gethin's men but they also turned their weapons onto the English firing a devastating arrow assault into their lines and disrupting it just as the Welsh infantry charge connected.


- Stage 4: English Rout

Order within the English force broke down and those able to do so fled. Adam of Usk quoted 8,000 men killed, undoubtedly a huge exaggeration, and it is more likely casualties were closer to 1,000. Mortimer himself was captured along with Thomas Clanvow, a former Sheriff of Herefordshire. Other prominent English magnates were killed including Kinard de la Bare, Waiter Devereux and Robert Whitney. Although unlikely to be completely true, contemporary chroniclers recalled barbarous acts following the battle. In particular the female Welsh camp-followers allegedly cut off the genitals of the dead English soldiers and stuffed them in the dead men's mouths and also cut off their noses and showed them up their anuses. Furthermore they denied the dead men a Christian burial.




The battle was an overwhelming Welsh victory which prolonged the rebellion of Owain Glyndŵr and destabilised English politics. Henry IV, his options limited due to the contemporary outrage from the alleged barbarous acts, led yet another army into Wales. Forces were mustered at Chester, Hereford and Shrewsbury in late August but by 7 September 1402 torrential rain was lashing the army forcing their withdrawal and another military failure for the King.


More significantly the defeat at Bryn Glas fuelled internal opposition to Henry IV who, following his seizure of the throne in 1399, was struggling to enforce his legitimacy. This was especially pertinent as he was descended from John of Gaunt, Edward III's third eldest son, whereas the Mortimers claimed descent from Lionel, Duke of Clarence who was the second son of that King. When Henry IV failed to pay the ransom to free Sir Edmund Mortimer, the magnate suspected the King saw an advantage in his continued detention. Outraged Edmund changed sides, issued a proclamation calling for his tenants to support the Welsh and married Glyndŵr's daughter to seal the deal.  This defection was bad enough for Henry IV but just weeks later the King learnt that the powerful Percy family, dominant in the north-east of England, had also risen in rebellion against him. Whilst the immediate threat would be eliminated following the Battle of Shrewsbury (1403), the net effect was the remainder of Henry IV's reign was marred by endless internal strife with the ongoing and unsuppressed Welsh revolt dominating the greater part of it.


The Glyndŵr rebellion would continue for the next seven years but, whilst he was never decisively defeated, his attempts to forge an alliance with outside powers came to nothing. Furthermore Rhys Gethin, the architect of the victory at Bryn Glas, was killed during an attack on Grosmont Castle in 1405 and this deprived Glyndŵr of one his best commanders - a shortfall that was all to evident at the Battle of Pwll Melyn (1405). Sir Edmund Mortimer remained loyal to his Welsh allies and died alongside them during the siege of Harlech Castle. However, when that fortress finally fell in 1409 the rebellion came to an end. Despite being offered a pardon in 1412, Glyndŵr himself refused to surrender and was never caught. His fate is unknown.



Breverton, T (2013). Owain Glyndwr: The Story of the Last Prince of Wales. Amberley Publishing.

Davies, R.R (2011). Owain Glyn Dŵr Prince of Wales. Y Lolfa.

Davis, P.R (2007). Castles of the Welsh Princes. Y Lolfa Cyf, Talybont.

Davis, P.R (2011). The Forgotten Castles of Wales. Logaston Press, Almeley.

Douglas, D.C and Myers, A.R (ed) (1975). English Historical Documents Vol 5 (1327-1485). Routledge, London.

Falkus, M and Gillingham, J (1981). Historical Atlas of Great Britain. Grisewood and Dempsey, London.

Gater, D (2008). The Battles of Wales. Gwasg Carreg Gwalch, Llanrwst.

Given-Wilson, C (1997). The Chronicle of Adam Usk 1377-1421. Oxford Medieval Texts, Oxford.

Griffiths, R.A (1972). The Principality of Wales in the Later Middle Ages. London.

Kenyon, J (2010). The Medieval Castles of Wales. CPI Rowe, Chippenham.

Knight, J.K (1977). Ancient Monuments and Their Interpretation. London.

Lancaster, J.H.D (2016). Bryn Glas: Battlefield visit notes and observations.

Lloyd, J.E (1912). A History of Wales. Cardiff.

Mortimer, I (2007). The Fears of Henry IV. Vintage, London.

Turvey, R.K (2014). The Marcher Lords.  Gwasg Carreg Gwalch.


What's There?

The battle was defined by the steep slopes of Bryn Glas and that can be clearly appreciated by a visit to the battlefield. The hill still dominates the landscape but whether the partial tree coverage seen today represents its fifteenth century appearance is unclear. St Mary's church, parts of which pre-date the battle, is normally open to the public whilst the churchyard gives superb views of the wider battlefield area. Castell Foel Allt, probably out of use by the time of the battle, can be found nearby.

Lugg Valley. A view of the Lugg Valley in which the battle was fought. The Welsh deployed on Bryn Glas, the hill to the right.

Bryn Glas. The hill on which the battle was fought is now partially tree covered. The clump of trees on the slope are Wellingtonia trees planted by Sir Richard Green-Price MP to mark the alleged burial mound of the Welsh troops. A memorial to the English troops can be found within the churchyard.

Castell Foel Allt. The remains of a motte-and-bailey castle, originally owned by the Mortimer family, can be found near the battlefield. Known as Castell Foel Allt, it was raised in the eleventh century but its condition at the time of the battle is unknown. The last recorded reference to the site dates from 1341 when it was still in use as a residence but, had it still been a viable fortification in 1402, some of the English forces would surely have sought refuge there.

St Mary's Church. The church was probably contemporary with Castell Foel Allt. The earliest masonry visible today is the tower which dates from the thirteenth century and was burnt by the Welsh forces before the battle. The site offers superb views over the battlefield.

Lugg Valley. The English advanced from the East. Pilleth and the site of  Castell Foel Allt can be seen in this picture.

High Ground. The high ground above the church where the main Welsh force mustered and charged the exhausted English as they scaled the steep hill.

Getting There

St Mary's Church is the centre of the battlefield and is found off the B4356 just to the west of Pilleth. The site is sign-posted and there is a dedicated car park incluidng an information panel about the battle. The remains of Castell Foel Allt, which was an abandoned earthwork at the time of the battle, can be found nearby and offers good views of the battlefield.

St Mary's Church / Car Park

B4356, LD7 1NR

52.307214N 3.092239W

Castle Car Parking Option


52.304981N 3.090072W

Castell Foel Allt

No Postcode

52.301910N 3.088526W

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