Dafydd ap Llewelyn, surnamed “Gam” from a cast in one eye, he was the grandson of Howel Fychan of the manor of Park Llettis, near Llanover, and fourth in descent from Einion Sais, who served in the battles of Crecy and Poitiers.
His father Llewellyn, purchased the estate of Penderyn, near Brecon, where probably Dafydd was born.
Dafydd also came into possession of the estate of Llantillio Crossenny. His seat in the parish was the castle called Hengwrt (Old Court), of which only the moat remains.
A local tradition has it that his progeny were so numerous that they could form a line reaching from his house to the church.
During one of the last campaigns of Owen Glyndwr against the Marcher Lords in 1412 Dafydd was captured and his house and lands at Penderyn ravaged by Glyndwr.
Dafydd was carried away into captivity and from some incident during his imprisonment there has arisen the Welsh legend that he attempted to assassinate Glyndwr during the meeting at the Welsh Parliament at Machynlleth in 1404.
Llewelyn ap Howel, father of Dafydd, received a commission from the King empowering him to negotiate with the Welsh prince for the release of his son in exchange for another Welshman. This was accomplished on condition that he did not again bear arms or oppose Glyndwr.
Dafydd was, however, soon in trouble again when in a brawl in the High Street of Brecon he slew his kinsman, Richard Fawr, Lord of Slwch (outside Brecon), and had to flee from the country.
Service in France
When that other son of Gwent, Henry V, was preparing for the invasion of France in 1415 Dafydd took service under him, together with his son-in-law, Roger Vaughan of Tretower, and a body of Welsh archers.
After being sent to reconnoitre the enemy before the Battle of Agincourt, he is stated to have reported to the King, “An’t please you, my liege, there are enough to be killed, enough to run away and enough to be taken prisoners.”
Si it proved, but in the midst of the battle he flung his body between Henry and the Duke of Alencon, receiving a sword thrust that was intended for the King.
As he lay dying by the body of his companion, Robert Vaughan the two were knighted by their Royal master.
Dafydd was immortalised by Shakespeare in the character of “Fluellen.”
Gladys, “Seren-y-Fenni” (Star of Abergavenny), the daughter of Dafydd Gam and widow of Sir Roger Vaughan, (married another hero of Agincourt, Sir William ap Thomas as “Y Milwr Glas” (the Blue Knight), from the colour of his armour.
Sir William ap Thomas purchased the sub-lordship of Raglan; his son, Sir William ap William, was a strong supporter of the Yorkist claims to the throne.
For his services, Edward IV in 1465 added the sub-lordships of Usk and Trellech to his Raglan estates, and created for him the new Royal Lordship Marcher of Raglan.
It is probable that about that time he commenced the building of the Raglan Castle that was to be the Royalist stronghold in the war against Cromwell.
As a reward for his capture of Harlech Castle in 1468, the King bestowed on him the title of Earl of Pembroke as a condition he had to adopt the English fashion and take a surname.
He chose the name of Herbert, after a supposed ancestor, Herbert Fitz-Henry, who had been a chamberlain of Henry I.
The new Earl of Pembroke was ordered to suppress the rebellion of Robin of Redesdale, but at Edgecote Field on July 26, 1469, he was defeated and captured. Next day he and his brother Richard Herbert of Coldbrook were beheaded at Northampton.
Lord of Glamorgan
His granddaughter, Elizabeth married Charles; the only Somerset to survive the Wars of the Roses; in 1514 he was made the first Earl of Worcester, and from him descends the line of the Dukes of Beaufort.
Another descendant of William Herbert, first Earl of Pembroke, married Ann, the sister of Katharine Parr; he earned the favour of the Protector, Seymour, for his share in suppressing a rebellion in the West Country, and was granted the Lordship of Glamorgan and then created Earl of Pembroke.
As a result of various marriage alliances, the lordship eventually came into the hands of the Marquis of Bute, the presenter holder.