Their power base had developed mainly as consistently loyal supporters of the de Bohun family, who were both earls of Hereford and Marcher Lords of Brecknock from the 13th century onwards.

"[4] Under Llywelyn ap Hywel, the family's traditional loyalty was transferred to the new Lord of Brecknock, Henry Bolingbroke, who had married Mary de Bohun in the 1380s.

Some say Dafydd was previously in service to Henry's father John of Gaunt and, having killed a rival in Brecon High Street, had to leave Wales temporarily.

The Scottish chronicler Walter Bower names Dafydd as a leader in the crushing defeat of Glyndŵr's men at the Battle of Pwll Melyn near Usk on 5 May 1405.

Records show that Dafydd Gam served with three-foot archers[clarification needed] in the Battle of Agincourt campaign.

By the Tudor period, this story was frequently being told in histories of the campaign and by the descendants of those involved, and it was widely accepted as the truth at that time.

George Borrow said of him, "... where he achieved that glory which will for ever bloom, dying, covered with wounds, on the field of Agincourt after saving the life of the king, to whom in the dreadest and most critical moment of the fight he stuck closer than a brother".

[7] Juliet Barker, while not accepting the rest of the legend, claims in her history of Agincourt that "Llewelyn was knighted on the field, only to fall in the battle."

[8] Some of Dafydd's descendants, who adopted the surname 'Games' to mark their connection to him, remained one of the most powerful families in the Breconshire area until Stuart times.

His daughter Gwladys ferch Dafydd Gam, "Seren y Fenni" ("Star of Abergavenny"), made two good marriages, the first to Sir Roger Vaughan, who also died at Agincourt.

George Borrow describes Dafydd in Wild Wales (1862) as follows: "He was small of stature and deformed in person, though possessed of great strength.

His influence on the play may have been greater still: in the words of the Oxford Dictionary of National Biography, Dafydd "may indeed, as has been suggested, be the model for Shakespeare's Fluellen, the archetypal Welshman".

The Latin inscription reads in translation: "David Gam, golden haired knight, Lord of the manor of Llantilio Crossenny, killed on the field of Agincourt 1415".