Battle of Bryn Glas, 1402: how Owain Glyndŵr captured Mortimer at Pilleth

The news reached Henry IV as he was preparing to send his daughter to Germany. Shakespeare later turned the moment into a scene: "a post from Wales, loaden with heavy news", reporting that the noble Mortimer had been taken by "the rude hands of that Welshman" and a thousand of his people butchered. The play is two centuries later than the battle, but the shock was real. For the first time since the death of Llywelyn, a Welsh army had destroyed a royal army in the field and taken its commander. The battle is one chapter in the military history of Wales.²

Background: why Glyndŵr rose in 1400

Owain Glyndŵr was a Welsh gentleman of the old princely blood: through his father he descended from the kings of Powys, through his mother from the royal house of Deheubarth. He had studied law in London and served the crown in war, certainly on the Scottish expedition of 1385. Nothing in his early life, the Dictionary of Welsh Biography observes, foretold what followed.³

On 16 September 1400, after a quarrel with his neighbor Reginald Grey, lord of Ruthin, Glyndŵr and a band of kinsmen attacked Ruthin. A Welsh source, the Royal Commission notes, has him proclaimed Prince of Wales that same day at Glyndyfrdwy. Britannica writes that the revolt quickly became a national struggle, fed by resentment of English rule. In June 1401 Glyndŵr, with perhaps 500 men, beat a much larger force of Welsh and Flemish soldiers from Pembrokeshire at Hyddgen, in the boggy uplands west of Pumlumon.⁴

In the spring of 1402 the raids moved south and east, towards the border. Earlier that year Glyndŵr had captured Reginald Grey himself. A large English force gathered at Ludlow to punish the raiders.⁵

Armies and commanders

The English. The army was placed under Sir Edmund Mortimer, a younger brother of the late Earl of March and uncle of the boy earl, Edmund, whose claim to the throne was a standing threat to Henry IV's new dynasty. Wylie describes his force as partly English of Herefordshire and the border counties and partly his own tenants from the hill districts of Radnor and Montgomery, many of them Welsh. In the middle of June it marched up the valley of the Teme.⁶

The Welsh. The Evesham chronicle, the fullest account, says Glyndŵr came down from the mountains with a few men and took his stand on a hill beside Pilleth. Wylie names Rhys Gethin, one of Glyndŵr's captains, as the leader of the Welsh that day. The Royal Commission writes that Glyndŵr was once again outnumbered, and no source gives his strength.⁷

The battle on Bryn Glas

The Wigmore chronicle places the battle "upon the hill called Bryn Glas in Maelienydd near Knighton". According to the Evesham chronicle, Mortimer fearlessly ascended the hill, and the two forces met with a great charge. The Royal Commission's summary of the evidence is that Glyndŵr's archers got the better of Mortimer's men, and that he had hidden soldiers at the side of the hill who fell on the rear of the English army.⁸

Who won the Battle of Bryn Glas, and why?

The decisive blow came from inside Mortimer's ranks. The Evesham chronicle says the Welshmen of Maelienydd turned against their own lord; Wylie writes that many of Mortimer's tenants joined openly with the Welsh and turned their weapons on their English comrades. The Royal Commission speaks of Welsh archers in Mortimer's army defecting to Glyndŵr. Wylie pictures the rest: men shot, stabbed, stoned or trampled in the crush of the narrow valley.⁹

Mortimer was taken in full view, the Evesham chronicle says, and many others with him. Among the dead was the knight Kynard de la Bere. The chroniclers disagree on the toll. The Evesham chronicle, as translated for the Royal Commission, counts about 400 English dead, four of them knights; Wylie cites a letter of the time for more than 1,100; Adam of Usk writes of "woeful slaughter even to eight thousand souls", a figure Wylie thinks includes the Welsh dead and came to Usk from a distance.¹⁰

Stories reached England that the Welsh, even the women, mutilated the bodies of the dead. Wylie reports them as rumor, if the stories were true, and Shakespeare made them part of the play, in lines on a "beastly shameless transformation" done by Welshwomen. No source close to the battle confirms them.¹¹

Aftermath: the captive who changed sides

Mortimer was taken into the mountains of Caernarfon and treated with honor. Glyndŵr asked Henry IV for a ransom, and the king refused. Suspicion fell on Mortimer at once: Wylie notes that he had been the go-between with the Earl of Northumberland, and that his lands near Denbigh had been conspicuously spared. He then married Glyndŵr's daughter Catrin and went over to the rising.¹²

Henry answered with a great three-pronged invasion in September 1402, said to number more than 100,000 men. It achieved nothing: Wylie describes rain, hail and storm from the day the armies entered Wales until they were driven back. Glyndŵr's alliance grew to include Henry Percy, Hotspur, who was killed at Shrewsbury in 1403, and later the Earl of Northumberland, with whom Glyndŵr and Mortimer signed the Tripartite Indenture of 1405.¹³

The rising peaked in 1404. Glyndŵr took Aberystwyth and Harlech, held a parliament at Machynlleth, was crowned Prince of Wales and made a treaty with France. Then the tide turned. After defeats in 1405, Britannica writes, his allies in England were crushed and French help could not save him; by 1408 to 1409 Prince Henry, the future Henry V, had taken his strongholds. Mortimer died during the siege of Harlech, Adam of Usk records. Glyndŵr fought on in the hills and after 1412 disappeared from the record; he was never betrayed.¹⁴ › Henry V: the victor of Agincourt

Why the Battle of Bryn Glas mattered

Bryn Glas made the rising more than a border war. The Royal Commission writes that the heavy defeat boosted Welsh support for Glyndŵr; the capture of a Mortimer, a kinsman of the rival claimant to the throne, turned a Welsh rebellion into a threat to the Lancastrian dynasty itself.¹⁵

Glyndŵr's program went beyond war: the title of Prince of Wales, the royal arms of Gwynedd, a national parliament and an independent Welsh church. The Royal Commission calls him one of the best known national heroes of Wales; Britannica notes that his fame grew with the revival of Welsh nationalism in the 19th and 20th centuries. Shakespeare gave him a romantic part as Glendower in Henry IV, Part 1.¹⁶

Where is the Bryn Glas battlefield today?

The small church of St Mary at Pilleth stands on the slope of Bryn Glas, above the valley of the Lugg. It is said to date from the 14th century and to have been partly destroyed in the battle; it burned again in 1894 and was restored. The Royal Commission notes the tradition of a mass grave on the hill.¹⁷

Where exactly the armies met is still unsettled. Besides the Wigmore chronicle's Bryn Glas, a note of about 1432 places the battle on a hill with a spring, and the Prose Brut on the "Blacke Hyll". Metal-detector surveys and excavation for the Royal Commission between 2012 and 2014 found no battle evidence on Bryn Glas, so the Commission concludes only that the most likely site lies in the vicinity of these three hills.¹⁸