Dafydd ap Gruffydd was the younger brother of Llywelyn ap Gruffydd, the Prince of Wales who ruled portions of Wales, to a greater or lesser degree, since the death of his uncle (also named Dafydd) in 1246.  The younger Dafydd was born in 1238, at least a decade after Llywelyn.  This Dafydd spent the majority of his life in England, to which his family was forced to come when his father was imprisoned at the Tower of London by King Henry.  At the time, Llywelyn had refused to leave Wales with the rest of his family, and thus was on the spot, so to speak, when his uncle Dafydd died. The family itself, however, was not imprisoned, and Dafydd grew up as a close companion to Prince Edward himself, a fact which could explain much of his later behavior.

At that point, Dafydd ap Gruffydd was only 8 years old, and in no sense prepared to put forth a claim to his patrimony.  When later he did, Llywelyn refused, and the lands that he acquired were given to him by his older brother, Owain, who had split Gwynedd equally with Llywelyn.  In 1255, believing he deserved more, Dafydd conspired with Owain to gain control of all of Gwynedd for themselves and were defeated by Llywelyn in the Battle of Bryn Derwin.  Llywelyn imprisoned them both initially, but then accepted Dafydd back into his favor a year later and gave him lands in eastern Gwynedd centered around Denbigh,which Llywelyn had taken from the English during the Rising of 1256. Over the next five years, he brought Dafydd more and more into his confidence until suddenly, in 1263, Dafydd defected to the English (and Prince Edward). To this day historians have no idea why though various apologists for Dafydd have suggested that he was dissatisfied with what he’d acquired from Llywelyn for his five years of loyalty.

To say that Dafydd had a problematic relationship with Llywelyn is woefully understate the case. Llywelyn kept Owain Goch imprisoned until forced to release him in 1277, but he released Dafydd after Bryn Derwin and gave him lands, ultimately bowing to his younger brother’s rightful claim as a prince of Wales. He was also, throughout his life, Llywelyn’s sole heir, as Llywelyn never had a son in or out of wedlock. At the time, Llywelyn perceived Owain, the elder brother, as the greater threat.

From Brynne Haug:  “Dafydd’s choice to turn to Edward in 1263 and again in 1274 was self-serving in that he believed his chances better with the king than with Llywelyn. Llywelyn had little choice but to accept Dafydd back when he changed his mind: in 1267 Edward I stipulated it in the Treaty of Mongomery, and it was again a condition in 1277.”

What’s more, in late 1274, Owain ap Gruffydd ap Gwenwynwyn confessed to Anian, the Bishop of Bangor, a man, by the way, who was not an ally of Llywelyn and often opposed him, that he had conspired with Dafydd to assassinate Llywleyn, the attempt being thwarted by a snowstorm. As J. Beverly Smith writes:

“The fullest account comes from a letter which the dean and chapter of Bangor addressed to the archbishop of Canterbury in the spring of 1276. Much of the substance of the letter is, however, corroborated by two documents from the critical year itself and  by an entry in the Brut y Tywysogyon. The dean’s letter relates that Gruffydd ap Gwenwynwyn and his eldest son, Owain, plotted with Dafydd ap Gruffydd to kill Llywelyn.  The conspirators had agreed that  Dafydd should remain in his brother’s entourage until 2 February 1274 when Owain would bring armed men by night to accomplish the deed, but a snowstorm on the night in question confounded their plans.”

Gruffydd acknowledged his guilt and actually retained much of his lands. Owain was imprisoned, as hostage to his father’s good behavior. Dafydd’s part in the plot appears to have been unknown to Llywelyn until late in 1274, when Dafydd was called to account for his actions (which he denied). It was only after Dafydd fled to England that Owain confessed to the bishop the entire plan, and Llywelyn understood fully what had been intended (Smith 1998 p. 369-373). Given Dafydd’s behavior in the past and future, particularly his pride and unwillingness to take second to anyone, Smith argues that Dafydd was the true instigator of the conspiracy (p. 376).

What must have been  most aggravating to Llywelyn was that Dafydd was one of the impetuses for all of the wars against England:  in 1267 and 1277 when Dafydd fought against Llywelyn on the side of the English, and again in 1282, when he forced Llywelyn to throw his weight behind Dafydd himself after Dafydd launched an attack on Edward’s castles in Wales.

Whatever his motives, Dafydd did stay true to Wales after Llywelyn’s death. In June 1283, English soldiers captured Dafydd, took him to Shrewsbury, and, in October, executed him.  He was hung, drawn, and quartered, and his head displayed in the tower of London alongside Llywelyn’s.

Sources:

J. Beverly Smith, Llywelyn ap Gruffydd:  The Prince of Wales.

Brynne Haug, Captive Cymru: Llywelyn and Gwynedd in the Wars of King Edward.

Peniarth MS 20, The Chronicle of the Princes